I successfully followed the instructions at https://kinsta.com/blog/create-wordpress-widget/ and got my custom widget to show-up in the list of plug-ins in a local instance of WordPress, and was even able to Activate it:
So now I have 2 questions:
I have never used WP, so please be specific. Where do I click?
Read more here:: Where to manage the settings for a custom plug-in widget?