iPhone Duo: Turn the Hinge Into an App Launcher

Open the Shortcuts app on your iPhone Duo.

On the "All Shortcuts" screen, tap the plus (+) button in the bottom-right corner. On the "What do you want your shortcut to do?"

screen, tap Edit in the top-right corner. Tap the Search field at the bottom of the editor, type "Automation," then under the "Display" section, tap Opened or Closed ("When my iPhone is opened"). Select Opened as the trigger in the editor screen, then search for the Open App action.

Tap the App placeholder in the "Open App" action, then choose the app you want to launch. In this example, we'll choose Kindle. Now leave the Shortcuts app – the automation saves automatically and is active right away.

You can rename the shortcut if you like, but it's not required.