Test tutorial instructions for advanced docs modification

[mekline]

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.

[ec6wellesley]

@mekline Did you want me to replace everything under "Advanced Instructions" with what you have written here in this issue? Or add this information in a specific location on the "Editing this documentation" page?

[ec6wellesley]

@mekline As I try to go through the advanced docs modification steps, I get stuck after the paragraph that begins with "If you are making substantial changes,...", which follows the "git submodule init" and "git submodule update". I tried inputting /lookit-docs $ virtualenv -p python3 denv, or variations of it, such as $ virtualenv -p python3 denv or virtualenv -p python3 denv. Could you give me any advice that could point me in the right direction?