Before you set up your accommodation, make sure you have set your "Room Types" in Settings > Room Types.
Room types are defined by name, type, gender and capacity.
For example you may have a private double room, and a shared double room. In this case you will need to enter two different room types and set one as private, the other as shared. Or you may have a mixed gender dorm and a female-only dorm.
See example below for common room types.
From here, you can set your various accommodations in the Inventory module. See this video for how to set your accommodation.