[Corvina]

Yeah, that's how it works. You create an account on their website, then you either scan the barcode you have or go to the main page and just click on the release you want to use your code with ( which is pretty easy, as all releases are listed there with a pic). Then you enter the code and voilà, you have the media file on your phone and can use it with the app.
In the app you can always listen to/watch your music or videofile with WLAN or you download the file on your phone to use it offline as well. But it just works together with the app. At least for videos.