I believe that user manual is available in the game, by pressing triangle from the opening menu, or thru the pause menu in-game.
As far as the XP question, it sounds like you set your progression to automatic. I know when I was simming seasons to tinker around with stuff, Demarcus Ware was hitting between 50k and 70k per year. There were a couple other players in the 40-50k, and generally all starters were above 25k.
As long as you set the progression method to anything other than auto, you'll be fine. Even at every week or every four weeks, you could choose to just let it pile up until the end of the season.