STARTING POSITION:
Select the appropriate resistance in the weight stack. Stand straight with your feet shoulder width apart. There should be a bar that is attached to a pulley higher than your head. Grab it with your right hand at shoulder width apart. Use a supinated grip. Your arms should be extended and the cable should have tension. Contract your pelvic floor and core while keeping your chest up.
MOVEMENT:
Contracting your biceps, fully bend your elbows while you exhale. Make sure you only move the forearms. Return to the starting position in a smooth movement while you inhale. The moving weights should not touch the rest of the stack.
TIPS: The exercise key is quality over quantity. The trick is to perform the exercise using proper form.