Add build instructions to readme

README.md

@@ -96,6 +96,16 @@ If you want to add or improve support for a language, read the documentation on
 
 Feel free to join us on the [Yomitan Discord](https://discord.gg/YkQrXW6TXF).
 
+## Building Yomitan
+
+1. Install [Node.js](https://nodejs.org/) and [npm](https://www.npmjs.com/).
+
+2. Run `npm ci` and `npm run build`.
+
+3. The builds for each browser and release branch can be found in the `builds` directory.
+
+For more information, see [Contributing](./CONTRIBUTING.md#setup).
+
 ## Third-Party Libraries
 
 Yomitan uses several third-party libraries to function.