If you wan to change the number of beds in the room (either add them or delete them) you should 
1. Make the changes in the backoffice of the booking portals. 
2. Then, changes should be made in the HostelSystem room settings:
- you should enter Manage--> Rooms & Rates
- choose a room and click Properties
- change the number of beds by using the #Beds option, see it over here.
3. New rooms should be mapped and synchronized in the HostelSystem xml settings, please watch our video tutorial how to see how to do it.