Set the cable to the lowest height then attach the ankle strap on the desired leg. Hinge forward to a 45-60 degree angle and grab the cable machine for support. Have your other foot firmly planted on the ground with a soft bend.

With a slight bend in the knee, kick your leg back and up in an arc until your heel is level with your hips. Then slowly lower it back down the same path to just in front of the other foot. Your heel should feel like it's swinging back. Repeat for the desired amount of repetitions.

Avoid kicking straight back instead of swinging in an arc and limit the use of upper body momentum.