Over the past couple years, we've had a series of posts on this blog aimed at helping to get new players up to speed on the game, so they know what to expect. They're linked below. You may want to read through them now before the season gets rolling, because once it starts... you'll be very busy.
Managing Your Prospects
The Importance Of Planning Ahead
Managing Your Minor League Pitching Staffs
The Worst Free Agent Signings In Ryan World History