Besides the partition standards, there’s no one set way to setup an XBOX. There are commonalities, but that’s about it. One person might have a F: drive with folders names Games, Apps, Emus, Videos, etc., while someone else may have them named Applications, Emulators, My Movies, and so forth.
And those with out an upgraded drive to the same things, but they have to do in on the free space available on the E: drive
That’s what makes this whole hobby so cool, the customization. On a personal note, that’s why I use XBMC as my main dash, because with the right know-how and the right tools, you can trick it out to be an excellent backbone for all your games, apps, and media (music, vids, etc). But many (oh so many) people will argue that it’s cooler/easier/better to just be able to make skins simply, for use with dashes like Avaluanch, UX, etc. But like they say, “Opinions are like assholes...” (you know how that one goes).
So, to answer your question, if you want to learn where and what everything on you box HD is, FTP and start looking around.
Just be sure and backup first…