iPhone/iPad (Safari): tap the Share button, then “Add to Home Screen”.
Android (Chrome): menu ⋮ → “Install app” / “Add to Home screen”.
Desktop (Chrome/Edge): the install icon at the right of the address bar.
Once installed, every piece in every key is stored on the device — it works with no network at all.
Key, tempo, metronome, count-in and staff selection are remembered per piece, automatically. “Save” stores them right away, “Reset” restores the defaults for the current piece.
Italian and English come from the Sibelius Academy Vaccaj site. The German translations are machine-made and may be rough.