Steps to build and use the Sphinx documentation tool:

1) Get Sphinx, sphinxcontrib-bibtex, and the RTD theme installed on your desktop from
    http:https://www.sphinx-doc.org/en/master/usage/installation.html
    https://sphinxcontrib-bibtex.readthedocs.io/en/latest/quickstart.html#installation
    https://pypi.org/project/sphinx-rtd-theme/
    
    For example: 
    pip install sphinx
    pip install sphinxcontrib-bibtex
    pip install sphinx-rtd-theme

    One approach that has worked to resolve "Module Not Found" errors for users with MacPorts package manager: 
    $ sudo port install py-six  # may not be necessary
    $ sudo port install py310-sphinxcontrib-bibtex
    $ sudo port select --set sphinx py310-sphinx
    $ sudo port install py310-sphinx_rtd_theme

    py310 can be replaced with the user's version of Python (e.g., py39) 

To build html:

$ cd ufs-srweather-app/docs/UsersGuide
$ make clean && sphinx-build -b html source build

The "make html" command can often be used in place of the previous command.

Sphinx uses Latex to export the documentation as a PDF file.  To build pdf:

make latexpdf

It will generate a PDF file in ./build/latex/<sphinx-project-name>.pdf