The exercise is to ride a big circle,  anything from 15m to 30m.   Balance the gait you are in ( i.e. walk or trot) then without changing the path of the circle,  bend or balance, transition to the next gait up.   Travel quarter to a half of the circle and transition back down, then travel quarter to a half circle and transition back up – repeat until it is easier.    If it does not get easier then decrease level of difficulty ( this could be by increasing the size of circle, increasing the distance travelled between transitions or changing gaits) or do less repetitions or take a spell in the other direction.