Sounds like you want the lock.
You can use Apple TV as a conference room display so that anyone can easily share their screen from a Mac or iOS device using AirPlay. When Conference Room Display is turned on, a message appears on the display with AirPlay connection instructions and wireless network details.
Enable Conference Room Display. On Apple TV, in Settings, go to AirPlay > Conference Room Display.
Create a custom message. In AirPlay settings, go to Conference Room Display > Custom Message, then enter your message. Your message appears only when Apple TV is in Conference Room Display mode.
Choose a background. In AirPlay settings, go to Conference Room Display > Choose Photo, then choose one of the photo-based background types. If you choose My Photos, the Photos app opens.
Preview Conference Room Display mode. In AirPlay settings, go to Conference Room Display > Preview.
Lock Conference Room Display mode. You can set Apple TV so that it’s locked in Conference Room Display mode until a 4-digit passcode is entered. In Settings, go to General > Restrictions, and enter the passcode if required. Then make sure Conference Room Display is set to Restrict in the list of restricted items.
Note: You use the same 4-digit passcode you set in Restrictions to unlock Conference Room Display mode. If you forget the passcode, disconnect Apple TV from the power outlet, reconnect it, then press and hold the button as it restarts. This will unlock Conference Room Display mode temporarily.