Michelle Berger explains how to do a Bulgarian or single leg squat. Have a bench behind you and step forward 2-3 ft. A good way to start is to have something to hold onto in the beginning. Simply place your leg behind you on the bench, lower yourself down, lower down perpendicular of the floor, make sure your knee does not go over your foot. You then push up through your heel, you should hold on as your doing this if you need to. There are many variations for this exercise where you can bring your leg in the front more forward, or you can continue moving up and down as if you were holding dumbbells. You would want to start with opposite legs first to not overwork your legs.