To get involved, follow the steps below:
First go to the homepage. There you should see a section in the right sidebar called "Test Spotify Connect".
Click on "sign up here".Then you will get redirected to a google docs form.
Then fill in your Spotify Community Username and your Spotify username. If they are already filled in, then double check the information and press Send (Verzenden in my language).
When everything is fine, you should see a "Thank you" page.