Adjust the machines seat height to allow your feet to be flat on the ground when seated and so the grips are roughly at shoulder height. Hold the grips at just wider than shoulder width.

Start by pressing up, like you're driving your biceps towards your ears. Press to the point where your arms are almost fully extended. Then lower back down to just before the starting position at a controlled pace. Keep your wrists aligned with your forearms and maintain a straight spine by activating your core throughout the exercise. Repeat for the desired amount of repetitions then rest the weight gently.

Avoid bringing your elbows behind your hips too far.