I was missing the old library filter control at the bottom of the library pane. I know, I know—there is a lovely gravity filter funnel icon at the top of the library pane that I did not even pay attention to (which is really bad for a retired chemistry teacher; it should have at least triggered a "what is that lab ware icon doing in Accordance" type of reaction.
When I opened the Tutorials, I decided to try the Easy grouping and 'Knowing Your Library' was at the top of the list. The Knowing Your Library tutorial was very well organized and introduced the general features of the Library. Indeed, I found the filter function and had a good chuckle at my lack of recognizing the control I was seeking earlier.
I look forward to investigating the other tutorials. Well done!
—Joseph the Chagrined