Location of public directory?

Hi: I’m working through the steps to deploy my website. But I don’t understand precisely where the /public directory should be created? In a subfolder of the cloned academic-kickstarter folder? In a subfolder of the html content I’ve created? Or in a subfolder of the cloned github pages folder with my user name?

When I run this
git submodule add https://github.com/sjkiss/sjkiss.github.git public

I get this:
'public' already exists and is not a valid git repo


I solved this.