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 accounts or extra users in the way (if there are, SafeGuard tells you exactly what to remove, and you can add it back right after — no factory reset, no computer).
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+ and Wi-Fi.
From the downloads page, install the SafeGuard app on the phone (allow installing from unknown sources if asked).
Open SafeGuard and tap "Set up" on the Quick Setup card. SafeGuard checks Wi-Fi and Developer options first. If Developer options is off: Settings → About phone → tap "Build number" 7 times (Samsung: About phone → Software information; Xiaomi/Redmi/POCO: "OS version" or "MIUI version"; OnePlus/OPPO: About device → Version), then come back to SafeGuard.
Tap "Open Developer options", turn on "Wireless debugging" and allow it on your Wi-Fi network. Allow notifications if SafeGuard asks — the code goes there.
Inside Wireless debugging, tap "Pair device with pairing code" and keep that window open. A 6-digit code appears.
Pull down the notifications, tap "Enter code" in the SafeGuard notification and type the 6-digit code. No need to switch back to the app. SafeGuard then pairs, sets itself as the phone's administrator and turns on system protection — all automatically.
If something is in the way (an account, a Guest user, Samsung Secure Folder...), SafeGuard shows exactly what to remove. Remove it, then tap "Check again" — no new code needed.
When you see "Setup complete", SafeGuard is locked in place. You can sign back in to the accounts you removed and turn off Wireless debugging.
Important: Android only lets SafeGuard lock the phone when no accounts or extra users are in the way. If setup stops, SafeGuard shows what to remove — remove it, tap Check again, and continue.
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.