A bit hard to say about blogdown because its book is outdated. Follow the RStudio blog to read when blogdown and its books are officially updated.
Read everything Alison Hill wrote!
A Spoonful of Hugo: How much Hugo do I need to know? (and other posts in the same series)
Also read the docs of the theme you choose.
You might not need to read Hugo docs, that are much longer, much more overwhelming: you mostly only need to read Hugo docs when you need to tweak or customize a theme.
If you choose hugodown, you can read the whole hugodown docs and probably should especially as hugodown evolves.
If you start using Hugo for your website…
Watch development on GitHub of blogdown / hugodown, of the theme
Subscribe to the blogdown issues that are interesting to you? E.g. support downlit for syntax highlighting
Also keep an eye on what’s happening for the package you are not using (blogdown or hugodown).
Personal website: take notes to not forget what you tweaked, etc.
Collaborative website: even Hugo users might not know your website structure!
RStudio community forum (RMarkdown category)
blogdown issue tracker is clear about where to ask for help and where to give feedback.
If you start tweaking Hugo templates, Hugo forum
If you use #blogdown or #Hugo currently (or are shopping around), I'm on the lookout for user-friendly themes with nice built-in layouts for making personal websites. Any favorites themes recently? Please share! 🦪 pic.twitter.com/pkAQGKgRAC
— Alison Presmanes Hill (@apreshill) November 19, 2020
Browse the gallery. Choose your theme wisely.
To give a less technical interface to a Hugo website, you could use a CMS, see for instance what Steph Locke set up in this website with Netlify CMS.
How I started: I needed to tweak one thing in an existing theme and I googled that thing; then I had to tweak one more thing; etc. Others might have built a theme from scratch.
Threads indicating resources for beginners and the lack thereof: 2018, 2019
What you must know according to Steph Locke
You don't need to know go to build Hugo themes imo.
— Steph Locke (@TheStephLocke) June 24, 2020
Intermediate "Hugo" knowledge is needed, & is:
- filesystem inheritance
- iteration (range, where)
- scoping (with, site, params, . )
- scalars, slices (aka vectors) , and maps (aka lists)
- control logic (if, comparisons)
The advanced level for themes is probably:
— Steph Locke (@TheStephLocke) June 24, 2020
- asset pipelines inc. Npm packages like postcss
- output formats (md, json etc) and extra layouts
- html & css advanced stuff
- data driven components ( data/ and get*() s)