Stand under rings or a low bar, grab it with one hand and walk your feet forward so you hang at an angle, arm straight and body straight from head to feet.
Row with one arm, driving the elbow back to bring your hand to your torso.
Lower back down with control until your arm is straight.
Form tips
Resist twisting your body: keep it square, facing up.
Walk your feet forward to make it harder, or back to make it easier.