docs: add instruction for using template repo

exampleSite/content/docs/getting-started.md

@@ -5,6 +5,18 @@ next: /docs/guide
 prev: /docs
 ---
 
+## Quick Start from Template
+
+{{< icon "github" >}} [imfing/hextra-starter-template](https://github.com/imfing/hextra-starter-template)
+
+You will be able to quickly get started by using the above template repository.
+
+<img src="https://docs.github.com/assets/cb-77734/mw-1440/images/help/repository/use-this-template-button.webp" width="500">
+
+We have provided a [GitHub Actions workflow](https://docs.github.com/en/pages/getting-started-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site#publishing-with-a-custom-github-actions-workflow) which can help automatically build and deploy your site to GitHub Pages, and host it for free.
+
+[🌐 Demo ↗](https://imfing.github.io/hextra-starter-template/)
+
 ## Start as New Project
 
 ### Prerequisites