In System Preferences click on Displays > Arrangement and deselect Mirror Displays.If you’d like to make changes open System Preferences. You can also change the resolution and other settings.
You can change this if you would prefer to use the TV as a second screen, for example. You will now see your screen mirrored on the TV.Find your Apple TV in the section under AirPlay 2 – it may be named after the room it is located in, depending on how you set it up.Click on the AirPlay icon in your menu at the top of your screen (a rectangle with a triangle below).Make sure your Apple TV and Mac are both on the same WiFi network – they need to both be connected to a WiFi network in order for the connection to be established (which is frustrating if there isn’t a WiFi network!).Plug your Apple TV into an HDMI port on the back of your TV.
