On Android 11 and newer you can set SafeGuard as the phone's administrator straight from the phone — no computer, no cable. It works through "Wireless debugging": SafeGuard connects to the phone from inside the phone itself and sets everything up for you.
Before you start — You need a device running Android 11 or newer with no active user accounts (just sign out of accounts temporarily in settings — no factory reset and no computer needed).
SafeGuard does all the work from inside the phone: it pairs with the phone over the local network, sets itself as the phone's administrator, and turns on system protection. All you need is a phone on Android 11+ with no accounts signed in.
On the phone, open Settings → Accounts and temporarily remove all accounts (Google, Samsung, etc.). No factory reset needed — you can sign back in right after setup.
From the downloads page, install the SafeGuard app on the phone (allow installing from unknown sources if asked).
Turn on Developer options, then enable "Wireless debugging" (Settings → System → Developer options → Wireless debugging). Leave this screen open.
Inside Wireless debugging, tap "Pair device with pairing code". A 6-digit code and a port number will appear.
Open SafeGuard, tap "Set up" on the Quick Setup card, and type in the port and the 6-digit code. The code expires quickly, so enter it right away.
SafeGuard pairs with the phone, sets itself as the phone's administrator, and turns on system protection — all automatically, inside the phone.
If asked, approve the protection (accessibility) permission. Then you can sign back into your accounts.
Important: The phone's administrator can only be set when no accounts are signed in. If SafeGuard shows an error, go back to Settings → Accounts, make sure every account is removed, and try again.
If pairing fails, reopen "Pair device with pairing code" for a fresh code — a new one is generated each time. Make sure the phone is on Wi-Fi.
Older device? Wireless debugging is only available on Android 11 and newer. On older devices, use the computer + USB cable setup method instead.