Main concepts to learn for developing themes based on Sage/Trellis/Bedrock

Hello, I just thinking what skills is needed to feel comortable with building themes based on Sage.
Right now i just feel little overload about all new concepts. Can you tell your experience about what is needed from basic concepts to advanced?
For example: First learn css, then sass, then templeate hierarchy, then templete tags, then, vagrant, ansible, then composer, then npm/yarn, then blade.php. then controllers, then webpack4, then passing data etc… but in more details.

I know that is basic and very general question but I just curios what you recommended to learn for begginners step by step.

You’ve pretty much outlined already what you need to know. Only things I’d add to that are:

  1. PSR-2 (code style standard)
  2. PSR-4 (autoloading standard)
  3. ES6 JavaScript