As you can see here, this move is simply a pushup with a rotation at the top. The focus here is obviously going to be upper body strength, but also core strength and stability with the added rotation. Try your best to go all the way down for a full range of motion. If you cannot go all the way down from your feet, drop to your knees for the pushup. The rotation at the top of the movement should be done from the feet. Also, note that only one foot stays on the ground during the rotation. If the right hand is coming up, the right foot should come up too. This will engage the core muscles more and make them work harder to stay balanced.