Install Ruby and Bundler.
There is .ruby-version
file for rbenv if you like.
You will probably need GCC, Make, AutoConf and NodeJS installed.
$ bundle install
$ bundle exec jekyll serve
If you are using Windows, it's better not to fight with Ruby Installer. I use WSL and works pretty flawlessly, except file change watching (see tracking issue). So you'll have to run this instead:
$ bundle exec jekyll serve --no-watch
To workaround lack of watching, you can do:
$ bundle exec jekyll serve --detach
$ while (bundle exec jekyll build --incremental); do sleep 5; done