Just search for “Playlister Screen” in the TVOS App Store. Your Apple TV needs to be an Apple TV HD or Apple TV 4K to be compatible with Playlister. To tell if you have an Apple TV that will work see if your Apple TV has the TVOS App Store on the main TV menu.
Playlister TVOS App Store Link: https://itunes.apple.com/us/app/playlister-screen/id1444335106?mt=8
To activate the Lite Apple TV go to your Screen Manager and click the "Activate Screen" button.
Open the Playlister Apple TV app and enter the code on your TV screen.