There is a user guide but I don't update it very often - I just don't get asked for it, and my excuse is that mobile apps ought to be self-explanatory. The latest is attached here.
And to get on the Beta team you need to go through these steps:
1. Get a Google+ account
2. Join the Google+ Community https://plus.google.com/u/0/communities/100638199649434481720
3. Make sure your device is set up with the account you use for Google+, so Google Play Store recognizes the device is associated with your account and your account is enrolled in the Beta program.
4. On the device, go to this URL: https://play.google.com/apps/testing/com.arubanetworks.arubautilities
5. Click on the 'become a tester' button on this page.
6. Now you should be in the program. If you haven't already, download and install Aruba Utilities and you should get the Beta version.
Best,
Peter T