hi @Wei22, if you want to rent out the rooms separately you need a separate listing for each room. You have one listing for all the rooms, at present. If one room is booked, all are booked according to Airbnb as it stands now.
It looks lovely, by the way!
But if you do make separate listings be sure to be very clear in your description about what spaces will be shared e.g. bathroom, entrance, kitchen etc. This is one of the areas where the most friction arises between guests and hosts - they didn't realize that they would be sharing a bath, living room, etc. And be prepared for guests NOT reading your description - so what I do is I confirm with them that they have noticed my steep stairs and spiral staircase. That deters some from continuing the booking process - I'd rather have them not book, than book and be unhappy and give me a bad rating. I do not use Instant Book for that (and other) reasons.
You could say in your reply, "Please make sure to read the description carefully and to notice that the bathroom and kitchen are shared with the host and with other guests" or something like that, whatever makes sense. Some people even embed a "code word" that guests have to find by reading the description and reply with it, and then the host confirms the booking. Guests do not read the description - my guess is one in 5 actually reads the description. They just look at price and pictures... You can caption your pictures to clarify, too - "Here is the SHARED KITCHEN" "This is the shared bathroom" etc.
Good luck! Susie
