Can someone please tell me how to program the transmitter for the garage door opener. If it matters, I have 96 Cadillac Deville

You have to set the dip switches in the new remote opener with the same settings of the dip switches on your garage door opener. This way they are matched and will work.

You need to know if you have a rolling code garage door opener in your house first. If your controller in your car has a red light, it isn't rolling code adaptable. If you have a green light or orange light, you are good to go. The instructions should be in your owners manual to do this. They ar not hard but can be tricky.

If you have a newer garage door opener in the house it should program.
You have 3 buttons on the garage door opener in the car. Hold the outer buttons together until the yellow light flashes rapidly. That clears any old garage doors that were programmed, then chose which button you would like to open your garage door in the car. Hold your existing garage door opener transmitter to car buttons fairly close and push the buttons on both and hold until the yellow light flashes rapidly again. It should have programmed.

Go to HomeLinks website. They will have detailed directions on how to program the remote opener.