It took me a while too. It isn't the most intuative process but once you know it, it is very simple.
When in your room, select the "I" (Information) icon on the lower left-hand portion of the screen next to the Globe icon. Once there you can change your room name and description. The other neat option is you can shut off the room furnishing option so your chairs don't ask you to move them when trying to sit down.
Hope that helps.