Install dependencies:

$ yarn global add gulp-cli
$ yarn install

Now you can simply build the site by using the following command:

$ gulp

The build output reside inside the build/ folder.

For example you can view it with Firefox:

$ firefox build/index.html


Go inside the documentation folder:

$ cd documentation

Install dependencies:

$ bundle install install

Build the documentation:

$ bundle exec jekyll build

You can manually browse it in the build/ (documentation/_site_/) folder or run bundle exec jekyll serve.

For more information on how the documentation works, check Jekyll and Just the Docs websites.