Press the Left Bumper while in game to bring up the Hand Explanation Table. Press Left or Right to bring up the Chip Trick Table. This shows you which ones you have unlocked and how to perform them. For example, Arrow Up, Arrow Up, Arrow Up means press up on the D-Pad three times. Very similar to performing "amps" in "1 vs 100", or special attacks in a plethora of fighting games.
Sigs are like a third arm...everybody has got one....uh, or something.