This will be my first campaign DMing and there´s going to be a lot of people in the campaign, and they´re all pretty rowdy and hyper. How do I do this?

The number one thing is to have a session 0. Meet before you start and talk about what kind of game you all (you and the players both) want. Combat heavy? Intrigue? Exploration? Decide on what kinds of characters they might want, and what, if anything you won't allow. Are evil characters OK? (if this is your first campaign, I'd recommend strongly against allowing evil characters.) Any classes or races you want to ban? Which books are they allowed to use? Will people get XP if they miss a session? If you have a game setting prepared, its good to discuss that with them, so they can know what to expect, and help guide their choice of background. If its going well, try and build the party a bit, figure out how everyone knows each other.

Set expectations for how people will behave at the table. Sometimes, if people are being rowdy, its because they don't actually like D&D (they may not even realize it), and they're bored. So make sure everyone actually wants to play. I don't know what you consider a big group, but if it's, say, more than 5-6 players, and they are all really rowdy, it might not work. You can run into situations where one player is doing something, and the others start to make trouble because they aren't involved. You might consider a one-shot or short published adventure to start, to give them an idea of what they are in for and be sure they want to play once they understand how the game actually works. I mean, there's always going to be side conversations and table talk, but the more people there are, the more this will be an issue, and unless you are good at leading small group discussions, you can quickly lose control of the game. To an extent, its up to you to give them an interesting story to play, but they have to be able to meet you part way and control themselves. Make that clear. Being the DM is a lot of work, and if you are going to invest the time and effort, they need to be willing to control themselves.

Start in short easily built modules and plan them out to the last detail then expect the party to ruin all your ideas, nut it will prepare your for eventualities 

i am a relatively new DM as well.

If you are doing your own story (which is fun and stressful at the same time), don't be afraid to collaborate with your players on the story.  Keep some ideas to yourself so that there is some aspect of surprise, but otherwise allow the players to give their opinions on story aspects. In the beginning of my campaign, i felt like i was the only one responsible for the story and would get stuck with writers block or less than ideal story lines/encounters/etc.  Once i started to ask advice from my players, it became more fun for all of us. 

Also, don't feel like you have to know all the rules and all the lore and all the details of each of the characters' sheets.  know some of the base rules but don't feel like you have to know everything in detail.  If there is a discrepancy, make a ruling during the game, then talk about it afterwards.  That way your game doesnt get stuck on rules and breaks the flow of the game.   Regarding the character sheets, know the basics.  but don't feel like you have to know each spell the wizard knows or the inventory of each rogue.  

Finally, don't feel like you have to have all the gear.  i used wrapping paper (with grid lines) and sharpies for battle maps and army figurines for minis. I kept track of damage on an excel spreadsheet because i am a nerd like that. 

I know from experience that you are plenty good as a player and will do fine as a DM