How do I connect my Squarespace site to GitHub?

I am about to start a real world Squarespace dev project and I would like to know how to connect my Squarespace site to GitHub. I followed the official documentation as far as I could and I have a local environment set up and can see push changes locally to production, but I would like this to exist in an official GitHub repo. 

Squarespace v7.1 sites have no capacity to be managed directly through git. All SS site code is stored in the SS backend and they do not allow access to it, except for what the site editor interface provides.

However you can use git/Github in your workflow. I do. You just have to manually copy and paste the code into the various appropriate fields in the SS editor code injection locations.

SS v7.0 sites have a developer mode and you can use git locally on your computer to manage mostly the templates for the site. You do not have access to the backend of the site, again except for the editor interface SS provides.

SS's target audience is not website designers/coders. It is for average folks who mostly don't care about code, repositories, version control, and etc.

This isn't to say there aren't designer/coders that use SS. And, SS does cater to those folks needs to some degree, But not at a deep tech level. SS is really designed for the DIY website owner who needs to get info out or sell stuff in a relatively easy fashion. Many sites are managed by their owners on a day to day basis but they also work with a consultant to handle the big issues, within the confines of what SS allows technically.