Points at the sandbox environment. Real sign-in (create an account or use your test account).
How to install (Android): tap Download (or scan the QR) → open the downloaded .apk →
if prompted, allow “Install unknown apps” for your browser → Install. These are test builds —
not from Google Play. NFC tap and QR-gate scanning work on real Android devices.
iOS testers: iPhone builds aren't sideloadable — those go through TestFlight once the Apple Developer account is set up.