how to use Library?

[tarkwolf]

I'm new to using this software and it looks very nice. I don't really understand how to use the library? I'm looking at the split view under library. I see at the top the xbox360 and the local files(there is one h264 video there). Under it are 2 other pans one on the left empty and the one on the right "device files". At the bottom has several buttons : move to device, copy to device, copy to pc, move to pc... etc.. I'm trying to figure out how this works? does it copy files to the xbox? what are the buttons used for?

thanks to all