Learn Python from an absolute beginner level through advanced web application and blockchain concepts
Currently, Github doesn't allow using the Fork button to mirror a repository and allowing it to be private. You can take the approach demonstrated here to fork/mirror into your own account and make the repo private or you can fork and then import. Using import is available in the top right menu under by clicking the plus (+) sign.
The benefits of forking is updates to the root repository can be pulled into your fork, allowing you to get updates while keeping your updates intact.