What is the exact model Apple TV box?
Identify your Apple TV model - Apple Support
Find your Apple TV model number - Apple Support
An on-screen instruction on how to use AirPlay with this device, is typically the “Conference Room Display”.
You may exit that screen by using the Menu button on the remote. It should then return to the normal interface.
If exiting that is blocked with a code, then there may be a restriction set on that device.
If exiting that is blocked without code, then the device may have an MDM device profile set (perhaps by the previous owner?) that prohibits other functions than Conference Room Display. The (previous) device manager should be able to remove that profile.
… menu it’s plink at my devise but not functioning
I don’t know what that means. Please elaborate.