Step 1. Click on the Menu Bar option on the top right of the screen. 

Step 2. Click on the Hostel Module under the Menu Bar.

Step 3. Click on Rooms on the left sidebar of the screen. 

Step 4. Click on Add Room on the top right of the screen. 

Step 5. Fill up the details of the room. And then, click on Save Changes at the bottom right of the dialog box.