How do I program the garage door opener in my Audi A6?

I can't seem to figure out how to program the garage door opener in my Audi A6. I've tried following the instructions in the manual, but it doesn't seem to work. Can anyone provide a clear step-by-step guide on how to do it correctly?

To program the garage door opener in your Audi A6, start by making sure your vehicle is parked in front of your garage door. Then, press and hold the two outer buttons on your car's built-in remote for about 20 seconds until the LED light starts flashing rapidly. Next, hold your garage remote close to your car's remote and press the button you use to open your garage door. The LED light will flash slower and then turn off, indicating that the programming was successful.