Devices you are owner from will initially sync their state with your account storage etc. and once done will show up on your device list in pantahub and you will have permissions to roll updates, change configuration or delete it.
Claiming: devices that do not have mdns support might have telnet support enabled
Flash your Pantavisor device (see PV release)
Boot up, telnet into your device and tail -f /tmp/pantavisor.log -> there you will see both device id as well as challenge getting logged