Sumo Windmills

First, go into a wide-legged squat, lowering your butt as far as possible. You won't be able to get anywhere near what the pictures suggest, but try to get your thighs horizontal or a bit lower. Forget the arm position - it's a little easier if you put your hands on your knees and I find that helps keep the back vertical, which I think is important.

Then go into "triangle pose" by straightening your legs and twisting the torso (turning one foot slightly makes it easier). Some feel this in their IT band; I hear crackling sounds in one SI joint when I do it.

Slowly return to the squat and then do the triangle on the other side and then back to the squat, which should be easier by this time, though the first time you do it, your quads may complain.