To run it locally you will need Ruby. Install it using https://rvm.io/ or https://github.com/sstephenson/rbenv or just use your system one.
bundle install
jekyll serve --watch
After bundle you can run Guard in separated console:
guard
Use LiveReload plugin (Chrome, Firefox) and you can forget about reloading the page.
That's it.
More to read about jekyll: http://jekyllrb.com/
To deploy your changes, just push commit to github master branch, site will be automatically regenerated.