This site was built using RStudio and the Distill package.
You can access to the complete code of this site here .
Some valuable resources that have helped me a lot are:
Building websites in R with Distill: It is a YouTube tutorial on building websites using Distill. Very detailed and great for beginners.
Distill for R Markdown: A useful blog that teaches how to develop not only websites but also articles and blogs.
rstudio4edu: An online handbook designed to help in the design of educational content using R Markdown. Many useful details.