This is a project template. To use it, click on the green Use this template button, select your own account as the owner, give it an informative Repository name, and select Private if you want to keep the data and analyses private until they are ready for publication. Then hit Create repository from template and wait a few seconds for the repository to get generated.
To make your entire repository public, go to your repository settings, scroll down to the Danger Zone and click on Make Public. If you do this, everything in your repository that is synched to github will be publicly available.
Alternatively (or in addition), you can make rendered versions (i.e. HTML files) of your notebooks easily available to the public as a GitHub-hosted (=free) website. This is nice if you want to let people see your fully compiled RMarkdown and Jupyter notebook reports. For an example of what this looks like for this template repository, go to https://cub-computational-tools.github.io/assignment_project/. For details on how to do these, take a look at the docs folder.