Using these Fisher & Paykel stove control knobs is easy. Just simply fit them onto the corresponding control points on your RA535EW stove. When you turn the knobs, you'll adjust the heat of the hotplates. As for precautions, make sure the stove is turned off and cooled down before installing or removing the knobs. This will prevent any burns. To maintain these knobs, clean them regularly with a soft, damp cloth. Avoid using abrasive cleaners as they can scratch the white finish. With proper use and care, these knobs will serve you well for a long time.