Separate out instructions in README.md for template users and their users

Specifically, the README tells users to run `git init`, which you will want to do if you have just created a new project using the template, but if you're someone using this repo, you don't want to run `git init`! Instead you should clone the repo first.

Maybe we should have separate sections in the README?

Start by reading README.md and identify the instructions intended for people creating a project from the template versus people using this repository directly. Separate those workflows so template users are directed to git init while repository users are directed to clone the repo, then verify both paths are clear.

Written by the indexing model from the issue text.