Hello @Boriana3 ,
If you are using the new listing editor, it is very easy: Go to Listings in the top menu, choose the listing (if you have one, it might skip this phase for you). Then, in Your Space, next to Photo Tour, there is a plus sign (+) where you can add a room or a space to your listing.
Don't forget to use good quality pictures. Wait for a sunny day and turn on all the light fixtures.
I hope this helps.