- Added notes on contributing

README.md

@@ -12,3 +12,19 @@ mkdocs serve
 ```
 
 In the root of the repository, if you get an error you will need to install some PIP dependencies.
+
+## Contributing
+
+If you would like to edit the documentation then please edit the files in `docs_src/` (and **NOT** in `docs/`). The former folder
+is used for the base documentation files and the latter is the result of the post-processing needed to be applied to the Markdown
+files before they can be used for generating the LaTeX-based book or the Mkdocs website.
+
+Once you have finished making your changes in the files in `docs_src/`, please then run the post-processing script:
+
+```bash
+./makemarkdown.sh
+```
+
+This should produce an updated file in `docs/` with the same name as the one you edited in `docs_src/`, **commit BOTH files** please.
+
+Then you're done!