"Learn Common Lisp by Example: QtGUI with EQL5"
(On Matthew D. Miller's blog, from a series of articles on GUIs and Lisp.)
After a bit of searching around on DuckDuckGo, I ran across this fantastic blog post on how to use EQL5. I had already gone through the preliminaries of building EQL on my Debian box and reading through the examples and tutorials. But this fellow goes into further detail about how to use QML to design the user interface.
I had never heard of Matthew D. Miller, his blog profile says he's from Oklahoma, and "I'm a DBA by day and a youth pastor by night. I love Perl." and also "Part-time dragon slayer," but his blog is full of posts on Common Lisp and Scheme. And he seems to have a talent for explaining things, because the blog post was well written and easy to understand. I hope I can find him on the fediverse.