Congratulations on entering your first tournament. When you go over these games, you should go online to an opening database to look up what you should have played. That's how you will learn it.
In this case, it's not difficult. After 1 e4 d5, you take the pawn and presuming he takes back with the queen, you hit his queen with your knight. You gain time. If he doesn't take back with the queen, he will try to take back with the knight. That takes time. There's really nothing else for him to do. If he does, you develop.
If you don't take, you end up losing the right to castle. You know that's bad.
11 Ke1? There is no prize for giving the first check. Why not Bc4 first attacking his f pawn, then Ke2 clearing the way for both rooks to get to the d file?
27 Bxb5 was a pretty good move.
Good luck with the rest of your games.

So I'm currently taking part in my first ever tournament IRL, in a <1000 rated grouping. First match didn't go my way, but I'd like to get some thoughts on where I went wrong, and what options I could have considered along the way, even after I was in trouble.
Be kind, I may have a lot of games under my belt in chess.com, but I am very clearly a rookie chessplayer and had the added stress of my first live tournament