Use a rope or straps, straddle the cable and step out into a wide stance. You should have lateral pressure going out the sides of your foot just like when you box squat, sumo pull, KB swing.....Reach your hips back and roll your knees out on the way down. To stand up, push out on your feet, squeeze your glutes and drive your shoulders back. Keep your low back arched. These can also be done with a choked band around the bottom of a rack.
3-6 x high rep failure