1. Tap "Download"
below and a "Marketplace Installation" alert will appear
asking you to allow downloads from AltStore LLC
2. Open the Settings app and there will be a new option,
"Allow Marketplace From AltStore LLC" at the top under
your Apple ID. Select "Allow"
3. Return to
this page, tap "Download" again, and another prompt to
install will then appear. Select "Install App
Marketplace"