A friend wants my help starting a dnd club for our school, and I've got pretty much everything done, but some members will have never played so I wanna help teach them. Just looking for some tips on it and stuff as I'm not a great teacher. So, how would you all go about it. 

Start with the basics - things in the PHB only.  After they have played a while with that, start letting them expend to other books.  

Good idea. Wish that's how I learned. I learned by diving head first into pathfinder, with ALL books allowed. It was too much, lol

Run a mock session, one that doesn't affect the story, bit of combat, explain what they have to do, start them off at level 1 (I prefer lvl 3) so they can learn their characters from the ground up. 

Start small, and build on their experience with more difficult things.

Print out a status condition guide for them so they have a quick reference as well.

Could potentially do that for the dice as well, especially for a combat cheat sheet. 

Focus on one major rule set each session. E.g., just combat, not skills in the first session. You might also ignore proficiency bonuses for a while as well as they can be really confusing.

D&D can seem daunting to the new player, what with all the expensive books of rules, and charts, and math and such. Rather than start by assailing them with lists of rules, start by asking them questions. "Who is your favorite fictional character, and why?" - "Do you prefer to resolve disputes with diplomacy or combat?" - "Sneaky or in-your-face?" - and of course... "Do you wanna blow sh*t up?" Let their answers guide you in helping them create their character. They don't need to know what all the stats mean just yet.

Then I would explain to them what D&D is, and what it is not. It's not a game that you can "win". It's not "players vs the DM". D&D is an exercise in group storytelling. It is improvisational theater, in which the cast is also the audience. It's a way of learning how to work as a team toward a common goal, and to listen to and respect each member of the team when they're having their "moment". It's a game. It's supposed to be fun! If you're not having fun, talk to the DM to try to resolve whatever the problem is. This game does require that players come to the table with a certain level of maturity and respect for one another. It's not the DM's job to give you a good time. It is everyone's responsibility to ensure that everyone is having fun.

During Session Zero be sure to discuss boundaries. Are there certain subjects or situations that certain players are not comfortable addressing? How much blood and gore is acceptable? Will profanity be allowed? Also lay out the Table Rules, such as "no cellphones at the table" - "let others enjoy their moment in the spotlight" - and of course "chaotic neutral does NOT mean chaotic d0ucheb@g". 

Then I would run them through a simple encounter. For example, they're walking down a road late in the evening toward a small town, where they hope to get some food and rest. A few goblins jump out of the woods to rob them. Roll Initiative! During this simple encounter explain what dice they need to roll for each action they are taking, and explain how each ability works as it comes up. It's better to learn by doing than to try to memorize pages and pages of rules out of context. 

Finally - after each session (especially at the beginning) remember to ask the group if they are having fun and if there is anything they need more clarification on. Let them absorb the information at their own individual paces. The important thing is not who learns all the rules first, it's whether or not everyone is having fun. And remember, just as they need to feel that they can always come to you - their DM - for help and answers, remember that you can always come here and ask the Forum Dwellers for help and answers too. 

HAVE FUN!