This is an awesome workout, it’s great for the glutes, hamstrings and quads. It even takes some balance to get this one done.
Start with one leg forward and both knees bent at 90 degrees. Now push your leg back to a position where the front leg is now in the back position. The same rules apply, be sure to have both knees bent at 90 degrees.
Balance will be challenging at first, but be sure to keep your core tight and you will do fine.