When Navigating through your CORE Apple TV app:
Arrow keys: Use them to navigate up, down, left and right
Return: Use the Return key to make a selection.
When opening Playback:
Arrow keys: Use them to navigate up, down, left and right.
Return: Use the Return key to make a selection.
Additional playback function keys:
F7, F9: Rewind and fast-forward.
F8, Spacebar: Play or pause content.
F4: This will return you to the Home screen. (On the third-generation Apple TV, you’ll use the Escape key, instead.)
F11, F12: Decrease or increase volume.
F3: Open the app switcher.