This is a barebones React app sitting on an ExpressJS server. As is, you can clone and navigate into the project directory, then run yarn start-dev or npm run start-dev to start developing your new project. In another tab, run yarn (or "npm run") build --watch to have Webpack rebundle the project live as it is updated. Run yarn start to simply serve up the latest build of your app.
The guide for how to create this project from scratch can be found here. I include the generated dist/bundle.js to show the full result of following that guide, but you'll want to remove and add that file to your .gitignore for developing your own projects.