GitHub - Getting Started with Repository

Hi,
I just created a new repository in GitHub. The screen looks as follows:


I need to add a Python file on my hard drive. Call it C:\MyPython\Test\Steve.PY
but don't see how to do so.

From what I remember from Git (not GitHub) at my last position, a repository points to a particular directory on my hard drive, from which point, I can access its subdirectories. Accordingly, if my repository contains three files (A.PY, B.PY, C.PY) I will see them on my screen.

Accordingly, how can I get started with something similar using GitHub?

Thanks,
Steve