I want to help some friends enter the worlds of D&D, and I think having a session zero may be a really good way to help them design their characters, figure out what kind of game they want to play, and ensure they have a balanced party.

What tips do you have for running a session zero?  What questions should I ask?  What are some good table rules to establish?  This will be my first time as a DM, so I plan to use a bought campaign, but I still want to give the players a positive experience, starting with session zero.

Thanks in advance!

I recommend that you make it clear any problems the players have with each other be resolved and if something happens that causes problems, tell them to deal with it. Also, if you're going to be running a more... family-friendly game, establish that players should follow these rules. I normally discourage metagaming and stuff like that. Also ask what they really want to do. Do they want to battle huge monsters, do they have a favorite monster from a book or movie? My players love the ranger's Apprentice series, and they asked for the Kalkara to be added in. I homebrewed a stat block and had them cage fight it. They loved it! It was very satisfying to see my players enjoying this fight so much. Make sure your players enjoy the campaign. I recommend giving yourself and your players plenty of time to go through this session zero. Since it sounds like they're new players, they will probably have thousands of questions. Be prepared for this. Patience is also something you'll probably need. A balanced party shouldn't really be a worry. If they tend to be more straightforward, let them know that this is a chance to try their more unorthodox plans. Any of your players that tend to be more energetic and chaotic, let them know that they might have to tone it down. Also its ok if you say no to some of their requests. That's all I got. Hope this helps!

A good thorough Session Zero covers three main categories of information. They all intersect to some extent, but it is important to address them all independently because it's better to cover something twice than to miss something that might become a problem later.

1. The World and the Characters.

     This is where you introduce your players to your game world and they build characters that fit into your game world. If you're using an existing campaign setting, and the players are already familiar with that setting, this part will be easier. But if you're incorporating a homebrew campaign setting, or if the players are new and aren't familiar with the canon settings, this is your chance to introduce them to the world. Some DMs think it's best to only show them a small part of the setting and to let them "discover through exploration". Personally, I think it's better to relay to your players whatever information about that world that you think their characters would know, having lived in that setting for their entire lives. And as they are building their characters, remind them that they are also building a team, so make sure all the necessary bases are covered - melee, ranged, arcane, divine, tank, stealth, survival, diplomacy, etc. It's also a good idea to allow your players to assist you in building out the world. If someone wants to play a thief, have them also describe their thieves guild and what its goals are. That sort of thing. That will help the players feel more invested in the campaign setting, and it's a great brainstorming exercise to come up with new story arcs.

2. Theme and Tone.

     A campaign's theme is the style of adventure the players can expect - is it a pirate campaign? - a long dungeon crawl? - a court intrigue campaign? - a land war in Asia? This will help them build characters that are prepared to face those challenges. If they all build pirate characters and you were planning to run them through a frozen mountain range, you're gonna have a problem. The theme is the "what's gonna happen" of the campaign. Tone, however, is the "HOW does it happen" of the campaign. Will the campaign be fun and playful, or gritty and grimdark? Will the campaign have steampunk vibes, or classic high fantasy? This is also the place to discuss any House Rules you'll be using. Maybe you want a fast-paced slasher campaign, so a short rest is 10 minutes and a long rest is 4 hours. Or maybe you want more realism, so a short rest is 8 hours and a long rest is 1 week. Maybe every time someone comes back from zero hit points they automatically get a level of exhaustion. Whatever your ideas - discuss them with your players to ensure that you're all on the same page and that you're all looking to play the same kind of campaign. 

3. Lines and Veils. 

     This section is an opportunity for you and your players to define the boundaries of the campaign's theme and tone. "Veils" are things that cause your players concern and which may make a scene or a setting uncomfortable or awkward. Lines are absolute limits that shall not be crossed. Some common veils are violence toward animals, overt racial discrimination, political references that mirror real-world politics, and claustrophobic environments. These are issues that may cause someone to withdraw from involvement until that scene has passed. Sometimes it is enough to inform the players during Part 1 that certain unpleasant elements do exist in the campaign world, but they will only be seen from a distance and the characters will never actually have to confront them face-to-face. A veil is literally that, something that prevents us from seeing something too clearly. Thus, it is important to inform players in advance what kinds of issues may be coming up in the next session or two, to give them the opportunity to emotionally prepare for that issue or to choose to sit out for a scene. 

Lines are much more serious, however. A line is a boundary that shall never be crossed, as doing so will cause severe and lasting distress. Examples of common lines are: abuse of children, genocide, brainwashing (such as through Modify Memory or Dominate Person), sexual assault, ritual sacrifice, or the deaths of close loved ones. These are solemn concerns that must be taken seriously by everyone at the table. Each player (including the DM!) may contribute to the list of items that shall not be included, and everyone must respect those lines at all times.

And the discussion of lines and veils doesn't only happen during Session Zero. It is a continuous stream of communication during and after every play session. Before each session begins, remind the players what sensitive issues may arise during the session. Throughout the session, if anyone ever wants to "take a moment" - the game stops. If a player wants to sit out a scene while the rest of the party deal with the sensitive matter, they shall have that option. If a player looks withdrawn or uncomfortable it is the responsibility of not just the DM, but of every player, to take a moment and gently ask that player how they're feeling, and whether they would like to take a break. And at the end of each session, ask everyone how they're doing and how they think the session went. Sometimes someone may not even know that something will bother them, because they've never had to confront it before. So when they encounter it in-game they may experience a very sudden rush of anxiety or fear that can manifest physically, emotionally, or both. 

The success of a good Session Zero will often correspond to the emotional maturity of the players involved. If everyone at the table is a reasonably rational adult with at least a base-line empathy, everything will go fine. If not - it won't. So it's best to weed out the immature players at the beginning before they have the chance to metastasize into a serious problem down the road that will ultimately doom the entire campaign for everyone.

Hope this helps.

Session Zero are a great way to lay down table rules, scope of campaign, player's soft and hard limits, houserules and optional rules, authorized material for character creations, other game limitation, party composition and character development etc..

Session Zero: Some Dungeon Masters start a campaign with a “session zero,” an initial gathering focused on creating characters and setting expectations, including topics to avoid as well as those to embrace. A session zero provides a great opportunity to talk to the other players and the DM and decide whether your characters know one another, how they met, and what sorts of quests the group might undertake together.

Quote from AnzioFaro >>

A good thorough Session Zero covers three main categories of information. They all intersect to some extent, but it is important to address them all independently because it's better to cover something twice than to miss something that might become a problem later.

1. The World and the Characters.

     This is where you introduce your players to your game world and they build characters that fit into your game world. If you're using an existing campaign setting, and the players are already familiar with that setting, this part will be easier. But if you're incorporating a homebrew campaign setting, or if the players are new and aren't familiar with the canon settings, this is your chance to introduce them to the world. Some DMs think it's best to only show them a small part of the setting and to let them "discover through exploration". Personally, I think it's better to relay to your players whatever information about that world that you think their characters would know, having lived in that setting for their entire lives. And as they are building their characters, remind them that they are also building a team, so make sure all the necessary bases are covered - melee, ranged, arcane, divine, tank, stealth, survival, diplomacy, etc. It's also a good idea to allow your players to assist you in building out the world. If someone wants to play a thief, have them also describe their thieves guild and what its goals are. That sort of thing. That will help the players feel more invested in the campaign setting, and it's a great brainstorming exercise to come up with new story arcs.

2. Theme and Tone.

     A campaign's theme is the style of adventure the players can expect - is it a pirate campaign? - a long dungeon crawl? - a court intrigue campaign? - a land war in Asia? This will help them build characters that are prepared to face those challenges. If they all build pirate characters and you were planning to run them through a frozen mountain range, you're gonna have a problem. The theme is the "what's gonna happen" of the campaign. Tone, however, is the "HOW does it happen" of the campaign. Will the campaign be fun and playful, or gritty and grimdark? Will the campaign have steampunk vibes, or classic high fantasy? This is also the place to discuss any House Rules you'll be using. Maybe you want a fast-paced slasher campaign, so a short rest is 10 minutes and a long rest is 4 hours. Or maybe you want more realism, so a short rest is 8 hours and a long rest is 1 week. Maybe every time someone comes back from zero hit points they automatically get a level of exhaustion. Whatever your ideas - discuss them with your players to ensure that you're all on the same page and that you're all looking to play the same kind of campaign. 

3. Lines and Veils. 

     This section is an opportunity for you and your players to define the boundaries of the campaign's theme and tone. "Veils" are things that cause your players concern and which may make a scene or a setting uncomfortable or awkward. Lines are absolute limits that shall not be crossed. Some common veils are violence toward animals, overt racial discrimination, political references that mirror real-world politics, and claustrophobic environments. These are issues that may cause someone to withdraw from involvement until that scene has passed. Sometimes it is enough to inform the players during Part 1 that certain unpleasant elements do exist in the campaign world, but they will only be seen from a distance and the characters will never actually have to confront them face-to-face. A veil is literally that, something that prevents us from seeing something too clearly. Thus, it is important to inform players in advance what kinds of issues may be coming up in the next session or two, to give them the opportunity to emotionally prepare for that issue or to choose to sit out for a scene. 

Lines are much more serious, however. A line is a boundary that shall never be crossed, as doing so will cause severe and lasting distress. Examples of common lines are: abuse of children, genocide, brainwashing (such as through Modify Memory or Dominate Person), sexual assault, ritual sacrifice, or the deaths of close loved ones. These are solemn concerns that must be taken seriously by everyone at the table. Each player (including the DM!) may contribute to the list of items that shall not be included, and everyone must respect those lines at all times.

And the discussion of lines and veils doesn't only happen during Session Zero. It is a continuous stream of communication during and after every play session. Before each session begins, remind the players what sensitive issues may arise during the session. Throughout the session, if anyone ever wants to "take a moment" - the game stops. If a player wants to sit out a scene while the rest of the party deal with the sensitive matter, they shall have that option. If a player looks withdrawn or uncomfortable it is the responsibility of not just the DM, but of every player, to take a moment and gently ask that player how they're feeling, and whether they would like to take a break. And at the end of each session, ask everyone how they're doing and how they think the session went. Sometimes someone may not even know that something will bother them, because they've never had to confront it before. So when they encounter it in-game they may experience a very sudden rush of anxiety or fear that can manifest physically, emotionally, or both. 

The success of a good Session Zero will often correspond to the emotional maturity of the players involved. If everyone at the table is a reasonably rational adult with at least a base-line empathy, everything will go fine. If not - it won't. So it's best to weed out the immature players at the beginning before they have the chance to metastasize into a serious problem down the road that will ultimately doom the entire campaign for everyone.

Hope this helps.

 Thanks for taking the time to respond so fully.  I have added these things to my plan to make sure we discuss them.  It is definitely helpful!

Quote from Plaguescarred >>

Session Zero are a great way to lay down table rules, scope of campaign, player's soft and hard limits, houserules and optional rules, authorized material for character creations, other game limitation, party composition and character development etc..

Session Zero: Some Dungeon Masters start a campaign with a “session zero,” an initial gathering focused on creating characters and setting expectations, including topics to avoid as well as those to embrace. A session zero provides a great opportunity to talk to the other players and the DM and decide whether your characters know one another, how they met, and what sorts of quests the group might undertake together.

 Thank you, my friend.  I knew I had seen information about running a session zero, but it is hard to locate in all of the material that is available.

Quote from IMPLAYS >>

I recommend that you make it clear any problems the players have with each other be resolved and if something happens that causes problems, tell them to deal with it. Also, if you're going to be running a more... family-friendly game, establish that players should follow these rules. I normally discourage metagaming and stuff like that. Also ask what they really want to do. Do they want to battle huge monsters, do they have a favorite monster from a book or movie? My players love the ranger's Apprentice series, and they asked for the Kalkara to be added in. I homebrewed a stat block and had them cage fight it. They loved it! It was very satisfying to see my players enjoying this fight so much. Make sure your players enjoy the campaign. I recommend giving yourself and your players plenty of time to go through this session zero. Since it sounds like they're new players, they will probably have thousands of questions. Be prepared for this. Patience is also something you'll probably need. A balanced party shouldn't really be a worry. If they tend to be more straightforward, let them know that this is a chance to try their more unorthodox plans. Any of your players that tend to be more energetic and chaotic, let them know that they might have to tone it down. Also its ok if you say no to some of their requests. That's all I got. Hope this helps!

 Thank you for responding.  These are great thoughts, and I am keeping them in mind as I prep for the session zero.