The Customize View Pic I've attach shows you the window when you do...
Right-click Audio in the tree and click Customize View...
In the Pop-up window, change View As: to Categories
Edit the Show Categories In This Order to customize the levels.
My suggestion:
Album Artist or Album Artist (auto) - check Grouping (i.e. A-C, D-F, etc.), Grouping Size: 1
Album Artist or Album Artist (auto)
Album or Year - Album
View As: has serveral options (Panes, Catagories, 3D, File List, & Chart), you want
CatagoriesBelow this, under
Show Categories In This Order, you can add library fields. In my pic I set it up as suggested above.
The Thumbnail View pic I've attached show you the menus on tab. In my pic it has Workout, on your 2nd pic it has Catagories
Hover over the tab Categories (your 2nd pic) until a drop down menu appears. Click List Style > Thumbnails