Change Library View

By default, the Library displays the music in a tree.  You see a folder per artist.  And then you open the folder to see all the songs for that artist.  You can change how the music in your library is organized.  The music can be organized into five formats:

 

View by All Songs (This is the only flat view.)
View by Artist (default)
View by Album
View by Artist/Album
View by Genres

 

Change Library View

Select Options > Library > Desired View.

 

Expand & Collapse All Folders

In addition, if the view has folders, you can expand or collapse all of the folders.

 

Select Options > Library > Expand All  (or Collapse All)