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What is your model Apple TV? Identify your Apple TV model - Apple Support
What is its version system software?
Apple TV (2nd and 3rd generation): Understanding AirPlay settings - Apple Support
It looks like your Apple TV is set to Conference Room Display. That settings is not necessary for home setups (more suitable for businesses and schools). Use Menu on the remote to exit the CRD screen. You can disable it in Settings, if you want. Settings﹥AirPlay﹥Conference Room Display﹥On|Off.
To connect your Apple TV, verify the network settings. There you can select a Wi-Fi network. Ethernet will be used if anything is plugged into the ethernet port. If the Apple TV is still not connectable there, then restart both the router and the Apple TV.