UPDATE May 24, 2022: Bumped jekyll and github-pages versions.

Here are some workarounds I discovered while troubleshooting things that didn't work for me on Mac when I tried to follow the GitHub.com Jekyll instructions. Jekyll is a blog site generator that works with GitHub Pages to create and host a free blog at https://your-github-accountname.github.io

At the point where the instructions said to run bundle exec jekyll VERSION new . or jekyll VERSION new . I couldn't make those work until I found these commands:

gem install jekyll -v 3.9.2
jekyll _3.9.2_ new .
# then edited Gemfile to select jekyll version 3.9.2, github-pages version 226
bundle update
bundle install # updated Gemfile.lock
# after that I could serve the site locally with the following command
bundle exec jekyll serve
# but note that you need to stop (ctrl-C) and restart for any changes to _config.yml to take effect

(I found the jekyll and github-pages versions here: GitHub Pages Dependency versions.)

Next I put everything in the docs folder (in the master branch), following GitHub's instructions, but then my site returned 404 - GitHub couldn't find anything. I fixed it by moving the files from the docs folder to the repository root folder. I guessed this solution because the repository settings page says "User pages must be built from the master branch." I didn't see the choices listed here.

Finally, I changed the Jekyll markdown in _config.yml to GFM (GitHub flavored markdown), because then blog pages are rendered nicely in GitHub's web view, like this page: https://github.com/sorenlassen/sorenlassen.github.io/blob/master/_posts/2020-05-09-my-jekyll-journey.md