Where do I do this?
Use the git clone command in your CLI
Copy the ssh-link on the top right in the tab "Code" and enter into your CLI "git clone your url"
What is the end result of this step?
What happens if I clone the original, not my forked repositry?
Even if you cloned the original repository, you still can edit files and commit them. However, you won't be able to push those changes back to the original repository unless you have write access. To fix this, simply change the remote URL of your local repository to point to your forked repository:
$ git remote set-url origin ssh-url-of-remote-repo
Now you can push your changes to your forked repository.