To add / delete rooms or change tables, you can access the menu at the top right.
With "New room" you will add a new one, give it a name and change its appearance and size.
With "Edit room" you can carry out the same operations for the room previously selected from the list.
With "Delete room" you can permanently delete the selected room
Note: the operation can only be carried out if there are no tables inside
The magnifying glasses at the bottom of the menu allow you to change the size of the room. The changes will only be visible in the operational phase, not during the modification.