The goal in the trick activity is to maneuver your body to match the poses shown on the screen. During a single flight you have at least 10 different poses to try and match. Once you match the pose just hold that position until the game checks it off. The faster you match the pose will determine how much more time and additional poses you might get. You need to reach 100 poses total but this is cumulative over all your sessions and does not have to be done in one sitting. Make sure you are signed in with the gamertag that you want to get the achievement for and it will count your total including single player and local multiplayer combined.