Removed the existing control knob. (Needed a miniature, thin long nose pliers to removed the retaining clip.) It should be noted that I ordered the knob retaining clip, but one was supplied with the new knob. This should have been stated in the description of the knob. Pressed the new knob onto the timer shaft until I heard the clip engage the timer shaft groove, then pulled back on the knob to make sure it remained in place on the shaft. Also didn't need to buy the timer dial as it was not part of the problem.