In order to use the Android TV application, first of all, you need to download it from the GooglePlay market on your TV.
After you download and install the application, you need to open it. And after opening you will see the following welcome screen:
We recommend logging in using the QR code, it is the easiest way. At first, you scan the QR code with your smartphone.
And then, using the browser you automatically log in to the app.
After that, you need to choose a game you'd like to play.
If you have already connected the external controller, you can start using it and playing.
In case you don't have a controller, you can use the gamepad app. To do so, you just need to enter the game.
Download the gamepad app and launch it.
Sync the gamepad app with the TV app.
You can start playing!