Set up properties and floors first, under Settings. Rooms are always added onto a floor.
Room and bed numbers are free text — 101, G-2, A or Bed 1 all work.
Room status is not something you set. A bed is available until a resident is assigned to it, occupied once they are, and release soon when their expected vacate date falls inside the release window.
Only an available bed can be deleted. To free an occupied bed, move or vacate the resident first.