I found a site that might help you: http://www.hoopsvibe.com/basketball-rules---definitions-article-419.html But to answer the question at hand:
Basically the fast break is gettin the rebound and gettin it out in "transition". The basic def of a fast break is gettin the outlet pass out and having numbers. If you have more with you on your team at the time then the other team does, I'd consider that a fast break.
As in a 2-on-1 or 3-on-1 fast break...meaning that there are 2 or 3 players moving towards the basket (one w/ the ball) against only one defender. This gives the player w/ the ball the option of taking it to the hoop himself against the defender, or dishing it off to one of his teammates so quickly that the defender can't react. It's what announcers mean when they say that a team "has the numbers". Basketball terminology is a whole different language, Geaux Girl. Don't ever be afraid to ask.