1)You need to install node modules in server(root). Command:
npm install
2)You need go to folder client. Command:
cd client
3)You need to install node modules in client.
npm install
4)You need go back in folder client(root)
cd..
5)Write a command to start project.
npm start
Change localhost in file :
client\node_modules\react-scripts\scripts\start.js