For me, the next step past https://arunrocks.com/minimal-hugo-site-tutorial was https://www.jakewiesler.com/blog/hugo-directory-structure
It helped me understand how to add plain markdown pages to a site that’s mostly hugo-reveal presenations, and that was a bloody miracle 
Clear doc is a wonderful thing. Seems like the official doc needs something like Jake’s doc added to it.
See Two kinds of pages in one site? for my painful learning experience, and https://github.com/dankegel/hugo-demo for my minimal demo.