So this took me about an hour to diagnose. Most of the documentation for adding a Drupal 8 library (groupings of CSS and JS) to a custom (thing) is based on a custom theme or child theme. So, they say you do the following in your mytheme.info.yml:
I spent much of the past 2 days deep in training on Drupal 8 module development. I'm using the fantastic Drupalize.me and the articles on Drupal.org. Even though I went though the OO-PHP training recently so more of the Drupal 8 stuff makes more sense than before, my head was still reeling from all of the new particles whizzing past.