The metronome app is not on the phone / play store or iOS app store. It's an app you have synced/beamed onto your garmin watch from garmin's own app store. The metronome app is a third party app found on garmin's connect IQ app store, and you send it to your watch. The one I'm trying out is called "Metronome" but eran\_levi found on the garmin connect IQ app store.