Get the TouchTunes app
On iOS via TestFlight
Step 2:
Redeem the invite
From inside TestFlight, tap "Redeem" and enter this code: qHiVzRk3
OR
Return to the TestFlight webpage and tap 'Start Testing' to redeem automatically
Step 3:
Install the beta app
Accept the invitation and install. You will see the app icon appear on your home screen.
Step 4:
Open the app & sign in
Use your existing TouchTunes account as normal