Think you'll need a retrofitter to code it for you.
"The Q7 can definitely have a heated steering wheel retrofit. Takes a slip ring/column switch assembly, wiring, steering wheel and coding work".
here's the link for the thread the above info cane out of:
https://www.audiworld.com/forums/q7-mkii-discussion-211/heated-steering-wheel-retrofit-2981646/
This also might help:
"did this retrofit last year to my Q7; got the steering wheel and stalks from eBay. Got some help from the A4 B9 forum, as the steering wheel and coding is mostly the same as in ours". Here's an account of my experience: https://www.audiworld.com/forums/a4-.../#post25288253