I was having some trouble and didn't see the instructions in the car manual (this might be posted already but can't have too many methinks).

1 Position the hand-held transmitter 1-3 inches away from the HomeLink surface*(usually located on your visor, overhead console, or mirror), keeping the HomeLink indicator light in view.
2 Using both hands, simultaneously press and hold both the desired HomeLink button and hand held transmitter button. DO NOT release until the HomeLink indicator light flashes slowly and then rapidly. When the indicator light flashes rapidly, both buttons may be released. (The rapid flashing indicates successful training.)
3 Press and hold the trained HomeLink button and observe the indicator light.
◦ If the indicator light is solid/continuous, training is complete and your device should activate when the HomeLink button is pressed and released.
◦ If the indicator light blinks rapidly for 2 seconds and then turns a solid/continuous light, proceed with the following training instructions for a rolling code device. A second person may make the following steps quicker and easier. Please use a ladder or other device. Do not stand on your vehicle to perform the next steps.
4 At the receiver (motor head unit), locate the “learn” or “smart” button (usually near where the hanging antenna wire is attached to the unit). If there is difficulty locating the training button, reference the device owner’s manual.
5 Press and release the “learn” or “smart” button (the name and color of the button may vary by manufacturer). NOTE: Once the button is pressed, there are 30 seconds in which to initiate the next step.
6 Return to the vehicle and firmly press and hold the trained HomeLink button for two seconds and release. Repeat the “press/hold/release” sequence up to 3 times to complete the training process.

 

My Homelink instructions were on a seperate card within the manual case. I've scanned them for anyone that may need it.

 

Thanks! I did manage to figure it out.

Its the same as the other procedures on other recent Audis, with one exception, the opener is not held at the front end of the car but a few inches away from Homelink unit inside the car.