Test tutorial instructions for advanced docs modification

Re: https://lookit.readthedocs.io/en/develop/contribute-edit-docs.html

This page gives instructions for setting up a github fork to make not just changes to individual pages, but more extensive changes like adding or rearranging pages on the website.

This can be approached as 2 tasks -

(1) Attempt to add a new page to the documentation, preview these changes locally, and make a pull request for this new page (which Melissa will review & then reject!) Confer with Melissa whenever stuck to identify missing tutorial information!

(2) In a separate branch, update these instructions to clarify any areas of difficult discovered during the process.