Lie on your stomach on exercise mat.
Prop on your elbows and make sure you are comfortable.
Straighten your legs.
Bend your left leg first.
All you are going to do is let your leg drop out to the side as far as you can go.
This is called external rotation.
And then allow your foot to drop in, and this is called internal rotation.
Perform this exercise as your range of motion allows you to do.
Slowly repeat several time