Apple has published a Knowledge Base article that shows how to arrange the Apple TV app icons on the main screen. The update, 5.1, also added Shared Photo Streams, AirPlay Send audio, iTunes account switching, Trailer searching, new Screen Savers, support for Subtitles, more advanced Networking options, and the standard stability and performance enhancements.
Arranging the app icons is really very simple, and Apple’s post shows us how it’s done.