This guide is targetted at 3 main audiences, and through this guide, I'd make sure to leave notes specifically for each of these kinds of audiences where relevant, but beware, I am writing this from the perspective of what I call "inventors".
Learners
You strive to understand how a compiler works under the hood, you have no desires to design a language
Inventors
You desire to create your own "production-grade" language and are interested in language design
Explorers
You don't intend to "ship" your language, you like creating many weird and esoteric languages for fun
(Like Nuc if you know him...)