Position yourself with your feet in the middle of the plate at shoulder width apart and your back against the padding. Press up past the safety locks then disengage the safeties with your hands.
Slowly lower yourself down by bending your knees until they are bent at approximately 90 degrees, then push back up in a controlled manner. Your back and hips should remain firmly against the padding by engaging your core to keep stability. Your knees should bend in line with your feet. Once you have completed the desired amount of repetitions, at the top of the final repetition engage the safeties, then slowly lower yourself down until the safeties catch the weight.
Avoid caving your knees inwards past your big toes.