For the back-end, install the dependencies once via the terminal.
npm install
Run the main server. It listens on port 3000.
node server
View it on the browser.
If you want to configure the front-end, go to react-src folder via the terminal.
cd react-src
Install the dependencies required by React once.
npm install
Run the development server for React. It listens on port 4200.
npm start
To make a production build, simply run on react-src folder via the terminal.
npm run build