how do i customise backgrounds and homescreen?

I have a couple of questions which ive spent hours trying to do and am about to give up, new to all this, using latest version on a android tv player

1. How do I change the standard background wallpaper. When i browse the main menu it would be nice to display artwork of the movies or tv programmes in my library. at the moment its gray images of cogs and things!

2. how do i add more 'furniture' to the home screen? one thing i'd like to be able to do is something like this... http://postimage.org/image/g4di5b8zb/

thanks!