Folders 01-Animations, 02-3D-Programming and 03_GLSL are for explanation section of fundamental knowledges.
Folder 04-Hans-on is for hans-on section. you can change these codes or make some thing new based on these.
Attached editor has features such as preview and auto-reload.
webgl editron is made by doxas.
https://github.com/doxas/webgl_editron
If you have preferring editor, you can use it instead of attached editor. In that case, you need a modern browser like chrome for preview.