How to close other apps on Apple TV using the direction buttons on the remote app?

I have gait issues and use directional buttons to make things easier. The problem is that I have figured out most of the functions. However, I haven’t figured out how to close apps.

How to use direction buttons on iPhone to close other apps using the Apple TV’s Remote app?

PS Why does Apple have these great products but hide their functions or do not create a thorough guide and or manual?

Sincerely,

Keith A Istré