Begin contribution guide

Author: namurphy

CONTRIBUTING.md

@@ -0,0 +1,27 @@
+[`Node.js`](https://nodejs.org/en/download)
+
+# Contributing to the Guide
+
+> [!NOTE]
+> This page is in the process of being written, and will largely be 
+> adapted from [PlasmaPy's Contributor Guide]. 
+
+## Submitting a pull request
+
+A contribution to this guide can be made via a pull request to the
+repository's `main` branch.
+
+## Building the site locally
+
+> [!NOTE]
+> It may be necessary to install a recent version of [`Node.js`].
+
+After cloning the repository, go to the top-level directory and run
+
+```bash
+python noxfile.py -s build
+```
+
+The build will be located at `_build/html/index.html`.
+
+[PlasmaPy's Contributor Guide]: https://docs.plasmapy.org/en/latest/contributing