1997 Mercury Sable Multifunction switch replacement

My husband is trying to figure out exactly how to replace the multifunction switch in our steering column, he knows that he has to pull the steering wheel. What else is involved, such as how to do take the spring that turns the wheel off and on, specs on replacing the switch etc? Any suggestions as to where we can find this information. We looked through teh Chilton and Haynes repair manuals and they were not very helpful.