To begin this exercise, you need four transition markers.
Place a pole parallel to the arena edge and complete a transition at each of these transition markers. There is no rule regarding the transition; you can do an upward, downward, or transition within the current gait.
Having a visual marker allows you, as the rider, time to prepare sufficiently for the transition. Over time you can add more markers as you see fit.
The goal of this exercise is to perform calm and relaxed transitions. You can also do a circle between markers/transitions to ensure you have a comfortable cadence from which to prepare your transition.