Download and manual link
We have parted with the installation of HockeyApp and have this awesome direct download link available:
Go there and follow the instructions. If you are upgrading from an older beta, make sure to uninstall the previous version first.
Still no luck :(
If you are sure you have gone through the entire manual and you still can not use the beta, let us know by email at firstname.lastname@example.org.
Have fun using the beta.