Have you downloaded the channel? Here it is in the US channel store:
If you can't find it in your channel store, it may not be available where you are. (Each content provider controls where their content is available.)
As for the code, each channel controls how they link up but it is typically, run the channel, the channel gives you a code and a URL. You go to the URL and enter the code and the channel is linked up on your Roku.