This feature is NOT available in the US - and also as far as I know not on the Q3 anywhere else either. It IS available on the Q5 however. It uses a camera mounted in the rear-view mirror mount and switches high and low beam automagically -
This is NOT the same as the standard tint assist of the mirror for oncoming or rear aimed bright lights in your mirror -
It is listed in the 2016 Owner's manual on page 40-41. I will give it a try tonight and see if it works. The manual shows that the high beam indicator light has a little "A" in the center of the blue dash light so it should be easy to tell. The headlight switch has to be in the Auto position and you push the lever forward. It also says to do the same to turn on the high beams manually.
Edit: I just checked and I do not see an "A" in my high beam indicator light no matter what I do with the lever. Since it is light out right now, I will try it tonight after dark, but I am not optimistic.