Most of the job is simple fastener mechanics. Use a nut driver or Phillips screwdriver. Remove rear panel.
Pull out control knob. If it is stuck, wrap a small rag around the back of it and pull the rag steadily.
Carefully match marked terminals on the replacement switch with those on original. Switch terminals may not be in the same location. Replace wires one for one, one at a time.
Carefully select the correct knob filler for the switch post. Several are supplied. Proceed with logic and measure the shaft length and the filler length and type to match.
First of all I removed the top panel then removed the switch. I then took pictures of the switch & drew a sketch with all the info. Then I went to your web site, matched up the switch & ordered. When the switch arrived I went thru the above replacing the bad switch.