STARTING POSITION:
Select the appropriate resistance in the weight stack. Stand straight with your feet shoulder width apart and the weight stack at your back. There should be a handle that is attached to a low pulley. Grab it with your right hand with prone grip. Take a step forward, you should be 1 meter from the weight stack. Extend your arm and move your hand just behind you. Contract your pelvic floor and core while keeping your chest up.
MOVEMENT:
Contracting your deltoid, raise your arm until your hand is at your face height while you exhale. Make sure you don't bend your elbow. Return to the starting position in a smooth movement while you inhale. The moving weights should not touch the rest of the stack. Repeat the movement for the specified amount of repetitions and then repeat with the other arm.
TIPS: The exercise key is quality over quantity. The trick is to perform the exercise using proper form.