Just add these two lines to the end (and unindent the entire file 2 spaces that were added for HN markup), and it should work with LaTeX, and then you can just make more instances of the `HeaderDateDesc` begin-end part, for each experience/degree:

  \end{HeaderDateDesc}
  \end{document}

If your LaTeX install is missing some packages, you might need to Google for how to add them.