No download. A code.

This site can be installed on a phone from the browser. On iPhone, use Share, then Add to Home Screen. On Android, use the install prompt when the browser offers it. That icon opens the same site. It is not a separate app, and it is not in an app store.

A team is one phone. The host reads a code, or you scan the QR. Photos are taken in the site, checked off on that line, and kept 90 days. Scores stay on your phone until the host reveals the end.