Open the link on the email from firstname.lastname@example.org
Tap the “1.Download” button.
Install the app on app Store.
Go back to the browser screen and tap “2.Configure”.
Once the app is open, swipe the screen from left to right and tap the “Settings” tab.
Tap the “internet calls (VoIP)” button.
Tap “Enabled on all networks”.
This completes the installation process.