Hi, I just did this Saturday. My wife ripped the mirror off. When to Orielly's autoparts and got the 1.79 kit.
There are you-tube lessons from the manufacturer (sorry I tossed the package). The instructions are as follows:
1) take the steel button out. It slides/yanks out. There is like a track on one side and flat steel on the other.
2) Clean off the steel button. I scrapped it and then sanded it. Cleaned in acetone.
3) Mark where to put the mirror attachment on the exterior of the windshield. (this means the outside).
4) Put a primer on the steel button. Let it dry. Takes about a few minutes.
5) scrap off the old glue from the windshield. I used a razor blade in a safety holder.
6) clean with windshield with acetone.
7) Apply a few drops of their glue to center of the steel button.
8) line the button up correctly and put in place. I think you need to hold it for 2 minutes (get comfortable).
9) let it dry for 24 hours.
10) Attach the mirror. It just slides on.
This took about 10 minutes.