@James1772
First, you need to add the photo tour to your listing. Airbnb will sort the photos automatically by room. You can reorder only the first 5 photos including your cover photo. Once the photo tour is created, you can go into the bedrooms (Rooms) and click and drag the photos in the order you want them. Don't forget to click the "sleeping arrangements" and add the bed size to your bedrooms. The first photo in the Bedrooms rooms will be shown under the Where You'll Sleep section.
Photo Tour
https://www.airbnb.com/help/article/477
If you don't like the fact that Airbnb shows the Living Room as the first room in the photo tour, come back here and we can explain how to get around that.