Install the dependencies...
cd svelte-webpack-ie9-multi-build
npm i
...then start Webpack:
npm run serve
Navigate to localhost:8080. You should see your app running. Edit a component file in src, save it, and reload the page to see your changes.
By default, the server will only respond to requests from localhost. To allow connections from other computers, edit the webpack-dev-server commands in package.json to include the option --host 0.0.0.0.
To create an optimised version of the app:
npm run build