Create a docs folder and go into it (cd docs) before calling sphinx-quickstart.
Put "sphinx.ext.napoleon" in extensions inside config.py. Also add these lines at the beginning of config.py:
import os
import sys
sys.path.insert(0, os.path.abspath('../..'))
Add the modules you want to document inside index.rst, don't forget indentation. You can also comment out the Indices and tables section.
Run in the console sphinx-apidoc -f -o source ...
Document your code with numpy or google docstrings.
Create your documentation in the console with make html or make latexpdf. If the ouput of make html doesn't seem changed after updating docstrings, use make clean before.