To operate the self-clean, set the oven controls to the Clean cycle then latch the door shut. Set the Start time on the clock for when you want to begin the clean cycle. Set the Stop time for 3 hours later. That's all there is to it. If the oven does not respond, you have other issues.
Easy-Off has developed a new spray for self-cleaning ovens that eliminates the need to use the self-clean cycle. After all, it is common knowledge among us repair folks that the self=clean cycle is hard on an oven, and your pocketbook. Not only does it burn 3 hours of electricity, but also can damage electrical parts from the extreme heat (900+
o F.) Even if you could make your oven work on this cycle, it may just be what kills it for sure

If it does not work, you may as well get Santa busy looking for a new oven, since very few parts are available for this model other than heating elements.