Start the hot-reloading webpack dev server:
npm start
Navigate to http://localhost:8080.
Any changes you make to your files (.elm, .js, .css, etc.) will trigger a hot reload.
When you're ready to deploy:
npm run build
This will create a dist folder:
.
├── dist
│ ├── index.html
│ ├── 5df766af1ced8ff1fe0a.css
│ └── 5df766af1ced8ff1fe0a.js