To run the game locally in development mode, just clone the repository and run yarn start
You can also use npm, just make sure to delete your yarn.lock file, otherwise you might have some complaining.
To run all test in watch mode (they will re-run on every change), you can run yarn test.
To run a local production build you can run yarn deploy. It runs all tests and builds the application if they pass. If you want to skip the tests, you can run yarn build directly.
The app also has automated build & deployment using Netlify. It runs on every commit that is pushed to master.