This is a bit long; in retrospect I probably could have split slices and maps into their own segments. Sigh.
Slides at: https://github.com/matt4biz/go-class-slides/blob/trunk/xmas-2020/README.md
Code at: https://github.com/matt4biz/go-class-counts
See also this neat visual cheat sheet: https://ueokande.github.io/go-slice-tricks
Take the opportunity to connect and share this video with your friends and family if you find it useful.