When installed the app will appear on your apps browser screen and just a click will launch it.
Its a very straight forward and simple process of just loading your picture, changing the tabs and browser bar colours and that's pretty much it, you save it and it becomes publicly available to those who want to download it. A file will save to your computer (don't worry its small and not harmful so say yes to downloading), click the button which appears at the bottom right of your viewer when its finished downloading and it will install. We will be looking at something for other browsers and mobile phone wallpaper at a later date.
Expect more themes coming your way for the fun of its, maybe you can try doing one yourself or there could be official GFC themes made.
If your brave enough, you can make this the theme to your chrome browser by just clicking the link HERE