Hi @Martin5987
Go to the Listings tab and click the listing. Click the photo to open the photo editor. Use the plus sign to add some more photos. The photo tour function requires that you move each photo into the correct folder that describes that room. This is important, as the information (bathrooms, bedrooms, beds and their photos) automatically pulls through to your listing description on the main page. For the same reason it's also important to tick the correct type of bed in each bedroom folder.
When you're done (everything in the correct place and all amenities ticked in each folder), click "All Photos" at the top and click your preferred cover photo. Above the photo you'll see the option "Make cover photo".