How do I set up erase and secure? My phone was stolen so I tried to erase from Samsung Device Manager but it just sends an erase instruction which I don't know whether the person who turns my phone on will be able to just stop from the device or not :(

Also the erase button on google device which sends a notification to the stolen phone to set up, the friendly thief ;) 

So I'm trying to not be in the same position again, I don't understand how to set up erase and secure from my new device.

Please help, Thanks
Remotely find, lock, or erase an Android device:


Go to android.com/find and sign in to your Google Account.


If you have more than one device, click the lost device at the top of
the screen.
If your lost device has more than one user profile, sign in with a
Google Account that's on the main profile. Learn about user profiles.

The lost device gets a notification.  
On the map, see about where the device is.  


The location is approximate and might not be accurate.
If your device can't be found, you'll see its last known location, if
available.

Pick what you want to do. If needed, first click Enable lock &amp; erase.


Play sound

Rings your device at full volume for 5 minutes, even if it's set to
silent or vibrate
Lock
Locks your device with your PIN, pattern, or password. If you don't have a lock, you can set one. To help someone return your device to you, you can add a message or phone number to the lock screen.
Erase
Permanently deletes all data on your device (but might not delete SD cards). After you erase, Find My Device won't work on the device.
Important: If you find your device after erasing, you'll likely need your Google Account password to use it again. Learn about device protection.



More informations: support.google.com