Setting your homelink involves possibly two steps.
The first step is to let your P-car learn what frequency and modulation to transmit on. This is done by, in essence, having your P-car's home link transmitter clone your handheld transmitter. If your garage door opener is an older unit that does not using "rolling codes" then, I believe, you are done. The button that you programmed above your rearview mirror will open and close your garage door.
If your garage door opener is a "newer" unit that uses rolling codes then you still have to go through the first step above (having your homelink clone your handheld unit) but now you have to climb on a ladder and push the "program or learn" button on the opener itself while then pressing the programmed homelink button in your car. This then synchronizes the rolling codes between the homelink and the garage door opener.
Once you get it done its not that hard! Its doing it the first time that can be confusing. Caution, I have inadvertantly pushed the "program or learn" button in such a way on my garage door opener that it erased its memory of all of the openers it knew about. This caused me to reteach all of my cars homelinks and even the extra handheld units I have.
Good luck!
