Me and a few friends are planning on starting a game, and it seems i'm going to be the dm. None of us have experience with d&d - even i have only played a couple sessions as a player. So none of us really now what we're doing, least of all me. Any tips on how to get started?

1. Do online research: Not to be a smart-ass, but scan through this forum, or search it, or search the Internet, for "How to get started as a DM". It's a topic that comes up a LOT, and there's a thread like this posted here about once a week, with lots and lots and lots of answers. People are more likely to help people who are already making an effort.
2. Start Small, Start Simple: I don't know what you have for books and resources, but the Starter Set is literally designed with you in mind. To begin, you really don't need more than the basic rules, some friends/Players-who-likely-become-friends-if-they-aren't-already, some dice, paper and a writing implement, and some sort of adventure. Don't try and kick off a level 1-20 campaign. Start with a single, simple adventure at first. That's it. Don't try to go and write a huge complex Tolkien quality campaign world. Start with 1 village, and 1 dungeon. The rest will come with time.
3. Embrace Mistakes, Embrace being Awful: Sorry, but we all suck at some point, we all sucked to begin with, and even those of us who have been doing this for years make mistakes all the time. You'll suck at first. The good news is that your Players probably won't care  - especially if they're relatively new, like you are - so don't beat yourself up for not being perfect. Work at getting better, and eventually you won't be awful ( as often ). But if you're paying attention, trying, and working with your Players, then you'll all have fun when you're awful, and you'll all have fun when you're good. Ride out the awful, and don't worry - everyone will have fun.
4. Follow the community, listen to it, but make up your OWN mind: There's no shortage of opinions out here. Listen to what people think and believe, and try and understand their viewpoint - why they believe what they do, what they're trying to accomplish, and whether or not they're succeeding. Then: make up your own mind. Absolutely no one will be an expert on your group and your game other than you. When you hit your stride, and it's working well, no one could run your table, in your style, other than you - not even Matt Mercer, or Matt Colville, or Chris Perkins. Your table, your responsibility - so your decisions.
5. Watch this guy: Matt Colville has a really good series on how to get DMs up from 0 to 60 with the least amount of pain. I'd recommend it highly. You could do a lot worse just downloading his introductory "goblin tomb" adventure from the first few episodes, and running that in your first session.  

It's perfectly fine to not know what you're doing at first, you'll make tonnes of mistakes but if you're willing to learn you'll do a great job. 

• The most essential thing for new players these days is Starter Set which comes with a pre-written adventure, a set of core rules, character sheets (blank and filled) and a set of dice. This is basically all you'll need to start playing and it's super reasonably priced. If you can't afford it on your own, do what my first table did and all chip in a little.
  
  
• If you do have extra funds for the Player's Handbook I recommend you buy it. It's the most useful book of all of them for learning how to play the game and learning the rules.
  
  
• When I started out I watched a tonne of youtube videos, but one of the most useful channels I found was Don't Stop Thinking who have a playlist for learning how to play.

As the DM, you need to have at least a good understanding of how the game runs. But don't spend more than 10 mins going over the rules with players before you start, after a quick briefing and rundown of the character sheets, jump straight into it and have them pick it up as they go along.

Lastly you don't have to follow every rule, if something seems too complicated (Spell components, XP Levelling, etc) then just drop it and work out your own way. Nobody from WotC is standing over your shoulder watching, the rules are mostly seen as guidelines to enable fun. That's the most important part, to have fun! Best of luck Dungeon Master!!

The main thing is just do your best; If everyone is new then any mistakes made will likely go unnoticed, and since it's unlikely you'll get everything perfect just focus on making sure everyone's having fun. Other than that you can run a good adventure with just the basic rules(which are free) and the things listed below.

Set the tone

Decide how serious the game is supposed to be and work from that. My rating scale for seriousness goes dark, heavy, casual, and meme, for example, and I think it's pretty easy to imagine what each of those entails. Decide what you want and talk it over with your players. Get on the same page so that somebody isn't trying to be serious and dramatic while everyone else is crab walking and robbing indiscriminately or vice versa.

Write the story

For example:

They start in the tavern, after some talking and introductions they're approached by NPC X and he tells them his house has been invaded by goblins. He wants the goblins gone and he's willing to pay them X amount of gold to get it done.

So now you have a place to start and a clear goal to accomplish. You can make it more complex and add more steps if you like, but something simple like what's above would probably work fine for your first game. 

Pad the story

Write up some random NPC personalities along with names. If you want to do this quickly, go roll on the Personality Trait, Ideal, Bond, and Flaw tables for a specific background and suddenly you have a somewhat interesting npc. Make a few of those and throw them in wherever it's necessary if the players ignore the hook and want to explore town for a bit.

You can do the same thing with places. Make a place, write down a few noteworthy details about it like "It always smells like cheese" "The decor is surprisingly nice given the neighborhood it's in" etc and now you have the framework for some interesting improv if the players choose to wander during the game time.

Build the adventure

Finally, it's time to add stats to everything. Common villagers, craftsmen, etc use the Commoner statblock available in the SRD. Goblins are part of the SRD as are many other monsters. All the base classes are available via the SRD along with one or more subclasses each.

It's also usually a good idea to script descriptions of places ahead of time like the starting tavern, or the inn in the slum that's super nice, or the goblin infested house; Practice reading it ahead of time if you want to do really well

Now you have a basic adventure, just like that. It'll probably take a bit of homework to get the actual mechanics of the game down, but it's not horrible. Do your research and keep something with Internet close by to rule check as needed. The basic rules can be found here if you haven't already found them.

I'm going to echo what others have said.

0) HAVE FUN

1) Relax, "fly casually".

2) It is your world, and their story,  let the players start small and become important.

3) Nothing works as "planned",  try to understand villain motivations and improv around that.

4) You are a collaborator, not an adversary (though Monty Python could disagree :)  As a DM you are invested in the world, not individual monsters. Put players in places to where they have to make interesting decisions.

Thanks for all the advice, guys! I hope this goes well, haha. I'm definitely going to need some luck, aaand a dozen cheat sheets, but oh well. We all agreed that we'll just try to have fun, even if it turns out we're playing totally wrong. 

If you all have fun, it's not totally wrong :) 

We can all improve and get better - but if your group keeps coming back, and they enjoy it, you're doing it right.

Best of luck :)

All great tips here! One thing I would mention is after your first few sessions ask your party what they like, don't like, what they want to see more of, and stuff like that. More than once I was doing some things that I thought was pretty cool or fun as a DM but from the player's persepective some of it just seemed like a chore.