Set up orbi to actually work

Does anyone have detailed step by step instructions on setting up the orbi rbr50 with the fiber service using this bgw210-700 I’ve tried everything I could find but I’m still getting a strict double Nat on my Xbox hardwired into the orbi. If the wireless signal on this gateway was better I would just use it but the Xbox and TVs on the other side of the house maintain weak signal on the gateway alone, and my ring doorbell can’t even get a signal to function