Don't know abotu instructions but the old folder sturcture used to be;
new format is;
In the iTunes Media folder is now separate folders for podcasts, TV Shows, Movies, Downloads, Automatically added etc, etc
How you get the new layout, move your music folder out of the iTunes>iTunes Music folder and then delete the library files, in your iTunes folder. Relaunch iTunes, it will recreate the folder structure in the new format. Reimport your library.
Yes, and playlists too unless you export them before hand. I don't use those features though so it wasn't a big deal for me.
If you keep going, piling upgrade on top of upgrade on top of upgrade and get patch after patch to the folder structure, eventually something is going to break and you'll end up having to redo it anyway.
Happened on two of the four PC's in my house so far. Transitioning to the current format, fixed the issue.