To start using this feature, make sure that the YouTube app is already installed on your TV. If YouTube isn't there, you'll have to install it the standard way. If this is a TV with Android OS, go to the Google Play app store, enter the desired application in the search box, select it from the results and install. Samsung has Samsung Apps. LG — Smart World. Sony — Sony Select. Philips — App Gallery.
 

More detailed information can be found on the website: