This is an interesting and innovative learning concept - presenting a .blend file with exercises and pointers.
Samuel Sullins writes:
Geometry Nodes are a pain to learn.
All that math and data and nodes.
The way I learned was by starting easy. Building a basic scattering system.
It's the easiest thing you can do, and you learn a lot from it.
I made this free demo file to help you do just that.
It includes explanations, node-by-node comments, and 2 simple scattering setups. All ready for you to play with and then rebuild in your own file.
If you're looking to learn Geometry Nodes, this is the best (and easiest) way to start.