To find the rules for FreeCell just open the app and tap the game screen background, anywhere beneath the cards. A menu will appear at the bottom, along with a little "i" in the lower righthand corner. 

If you press the "i" you'll see two options: you can either watch an interactive, animated "Tutorial" or read the "Rules" including the Setup, Objective, how to make Power Moves, and Scoring. If you scroll downwards in the Rules, you'll see a chart of the number of empty free cells and/or columns necessary to move a sequence of cards.