Adjust the seat height so your feet can be flat on the floor with your elbows in line with the pivot point of the machine and your triceps against the padding. Grab the handle/s with both hands where your elbows should be almost fully extended but not locked out.
Begin by bringing your wrists upwards until your hands are approximately at shoulder height. Pause briefly before lowering the weight back down in a controlled manner. Ensure that you are keeping your wrists in line with your forearms and that you are tensing the biceps when going up and down. Tense your core to keep your body stable throughout. Repeat for the desired amount of repetitions.
Avoid leaning back and using excessive momentum during the movement.