For this move start on one foot in the middle of the rebounder with a slight bend in the knee. Start with a small hop side to side and progress to bigger movements side to side, forward and back.
If you really want to challenge you can introduce the brain into the move and call out clock face positions (12, 3, 6, 9) and have people hop to the right clock face position.
This is a great exercise to strengthen the medial and lateral stabilizers of the knee hip and ankle joints. A very important for injury rehabilitation as well as prevention.