You can use
pip install antiweb to get the latest version of antiweb.
You need to set special directives inside your comments. Those are being interpreted by antiweb.
To generate the .rst file, navigate to the folder where
main.c (or your source file) is located and type:
antiweb <source file> <options>
In this case
antiweb main.c. That will generate a file called main.rst which can then be used by Sphinx for documentation.