npx create-react-app react-demo
npx command only works with npm version5.2+ and higher
npm init react-app react-demo
npm init command is available in npm 6+
yarn create react-app react-demo
yarn create command is available in Yarn 0.25+
Running of above command generate react-demo folder. it will generate self understandable folder structure like below screenshot.
npm start OR yarn start will open development server, you can access via http://localhost:3000 on browser.
npm run build OR yarn build generate the build of project to build folder.
Now you are ready to deploy.