VLC 2.0 - How to configure the Media Library?

VLC's Media Library is actually a special XSPF playlist, so managing folders and files in the Media Library view is comparable to that in the Playlist view.

After setting Preferences > All > Playlists > [x] Use media library as shown in the question body above, Right-click the area below the list columns (e.g. Title, Duration, Artist), and select an option from the context menu.

As an example, I have added my Music folder to the library.