do a search
If you do a search, there is a detailed list here, somewhere, that tells you the exact steps to follow. I used the list and it was very good.
If my memory serves me correctly, the first step is to use a butter knife to pry out the black plastic piece behind the silver inside door handle. Next is the removal of the gold screw, that is now exposed.... etc. You have to get the arm pull off first.
The only thing the list did not have is: for the front doors disconnect the door light, and for the rear doors, disconnect the door light and cigarette lighter.
Be careful, follow the instructions precisely because you could easily break some of the plastic parts around the switches. Crazy glue works wonders with the broken pieces!
1989 420 SEL