Based on my previous dealings with few audi seats, try to start from the top edge & get fingers behind slowly & I mean slowly prizing the back of so gives small gap & then if same as mine there are some clips at the top that need to be either popped of or moved to the side to release the back cover thus then lifts of as usually the bottom has some locating hooks that hook over the seat chassis at bottom, take care & patients & not to forceful, torch helps.
I will try & check elsa for precise guide, but in meantime try as above
Ok checked elsawin & it is the same as previous ones I've worked on as above, also & adding to above the back cover has some retaining clips at bottom that go under seat, these can be disconnected aswell but should be able to do as above without removing these at 1st, but hey try it anyway & also the sides of the back cover might be hooked over the seat chassis aswell, should all be obvious once you start tbh.