You have 2 options to deploy to GitHub Pages:
gh-pages) where you commit the generated filesIf you need to use your own custom domain, follow the GitHub docs from https://docs.github.com/en/pages/configuring-a-custom-domain-for-your-github-pages-site/about-custom-domains-and-github-pages
There is an official action from Zola: https://github.com/getzola/github-pages
Follow its README (don't forget to enable the GitHub Action source in the settings) and you should get your site up and running via the CI.
There is another action for that approach: https://github.com/shalzz/zola-deploy-action