Here is general help on tournaments:
http://www.chess.com/tournaments/help.html
In general, the rules are the same for (rated) tournaments as the rest of the site (i.e. be nice, don't cheat, etc.) but some TD have special rules for their tournaments.
I am a new premium member and just signed up for my first tournament. Since this website is so huge, I'm wondering where do I go to get information on the tournament rules?