For adding more circles in your rooms:
- Join any of your rooms room. You can see a list of them here
- Click on the circle to sit
- Click on This Room located at the bottom menu
- Click on Background and Editor
- You can duplicate the circles with ctrl+C - on mac as well.
Note that after customizing it and saving, you can not change back to the standard templates but you can still edit the customizations as many times you want.