Add README sample commands

Author: il-masaru-yamagishi

README.md

@@ -1,2 +1,24 @@
 # babylon-js-jp-community.github.io
+
 Babylon.js Japanese Community Website
+
+## Installation & Build
+
+- npm v20.x
+
+```sh
+$ npm ci
+$ npm run docs:build
+$ npm run docs:preview
+```
+
+## Debug
+
+```sh
+$ npm ci
+$ npm run docs:dev
+```
+
+## References
+
+- [VitePress | Vite & Vue Powered Static Site Generator](https://vitepress.dev/)