Place the belt securely on your hips and then hook it to the appropriate setting so that you can have full range of motion. Extend up and grab the handles to release the safeties.
Start by bending the knees, lowering yourself down until your knees are bent at 45 degrees or whatever is most comfortable before that. Then press through the heels to extend back to the starting position. Keep your core activated throughout the movement to maintain a straight back against the padding. Repeat for the desired amount of repetitions then hold at the top, engage the safeties and slowly lower yourself until the weights are caught.
Avoid rounding the back.