If you are on the left side of the step, you have to jump up on the step and land with all your weight on the right foot (lt foot flat). On the left foot you are on your lt toe. Next count shift your wt to your lt foot (on the rt you are on your toe, bearing little to no weight on the toe). Shift back and forth, bearing the weight on the flat foot. The other toe helps with balance.
It may help to think of shifting your hips. Stick one hip way out, then the other. Your weight follows your hip. Put all your weight in the "out" hip. Try this a while, bouncing back and forth and the feet sort of naturally follow along.
Once you get it, its loads of fun!