The article discusses the structure of documentation as three pillars: the what, the why, and the how.

I prefer to think about documentation in terms of four audiences:

- the student (tutorials)

- the chef (how-to guides)

- the theorist (explanations)

- the technician (API references)

Divio [1] has an excellent set of articles that explains this approach to documentation.

[1] https://documentation.divio.com/

The same excellent documentation framework is also available on this company-independent website: diataxis.fr