To create a room, there are several options.  
If you want to have a new partitioned room, draw walls around the area to be enclosed.  

If you want to define a room space without partitioning it, you need to draw the boundaries using the separator.  

Once the boundaries are correctly closed, a label and the room's surface area will appear.  

By clicking on the floor of the room, you will open its menu. In this menu, you can change the room's name, its numbering, manually adjust the automatically calculated living area, and select or make the floor covering non-editable by the buyer.