To automatically pair your TV and your mobile device, ensure they are connected to the same Wi-Fi network. Next, on your mobile device, touch or click the icon that has the symbol of a screen and Wi-Fi signal, and select the display on which you want the video to play.
If there isn't a Wi-Fi network around, you can manually pair your mobile device with a TV or game console using the pairing code of the TV or game console. To find the code, launch YouTube on your TV or gaming console, go to Settings, and the then Scroll to the Pair Device screen.
If your mobile device is on Android, launch the YouTube Android application, navigate to Settings, tap Connected TVs, and then select Add a TV. Next, enter the pairing code shown on your TV or game console. On an iOS device, launch the YouTube iOS application, go to Settings, and then select Connected TVs. As with the Android application, enter the pairing code of your TV or game console.
An alternative pairing method is using the YouTube mobile site. Launch the site on your mobile device, go to Settings, tap Connected TVs, then enter the pairing code of your TV or game console.