Test repository to get used to GitHub
One thing I've learned from the linked article is the suggested workflow of creating a new branch, working on that branch, and then creating a pull request to main when the suggested changes are complete. This is a workflow that I've seen used before in certain public projects that I keep track of, however it's not something I've done myself when I've tried to make additions to a public repository. Also, while I'm familiar with using GitHub as a general user, I've never really used many of their features in this way, in the past any time I would try to work with GitHub, I would first end up working on the files locally and then pushing them to the repository with Git for Windows. For making small changes and additions, just using the website seems likely more than enough for most people.