Hello - I thought that we had a DIY for the rear window regulator, but we only have one for the front window. If you're going to be working and maintaining the car yourself, consider getting a workshop manual for the E9x. It'll have all the procedures, torque specs, and diagrams that you'll need. I've attached a link below, please let us know if you have any questions.
https://www.pelicanparts.com/BMW/catalog/shopcart/BOOK/POR_BOOK_bkbnBW_pg12.htm