You will see the initial commit in your copy of the repository:

Now, click on cv.tex and update the cv with your particulars

Optionally, you can modify the index.html in a similar manner to add a Title and Description for the CV which may be useful in the link preview or for SEO.

These details are used when previews are generated like this:

Your CV will be available at https://username.github.io/repo_name/cv.pdf