To install all dependencies use
npm install
in boths folders ./frontend-online-shop/ and ./backend-online-shop/
Before running the app you have to run mongodb on localhost on port 27017, it can be done with the command:
docker run -d -p 27017:27017 mongo
Backend and frontend are running separately, because of it you need to run scripts in boths folders ./frontend-online-shop/ and ./backend-online-shop/ with the command
npm start