Once you've gotten up to speed on the game of baseball itself, I recomend checking out this
reddit post for some tips on how to set up your ootp game. You don't necessarily have to abide by it completely but there are some nice tips in there to check out that helped me when I first got ootp.
OOTP is an incredibly deep game, so it may be a bit overwhelming at first, especially for someone new to baseball. But I'd recommend reading up on as much about baseball as you can and just keep learning. Don't get discouraged; keep at it, don't stop learning, and eventually you'll be more than comfortable with the game.
