1.Type npm install -g create-react-app to Build React Project Enviroment

If you use npm 5.1 or earlier, you can't use npx. Instead, install create-react-app globally:

npm install -g create-react-app

Now you can run:

create-react-app mini-flicker 

2. Run the Code in Browser:

cd mini-flicker 
npm start

Creating an App
(npx is a package runner tool that comes with npm 5.2+ and higher, see instructions for older npm versions)
https://gist.github.com/gaearon/4064d3c23a77c74a3614c498a8bb1c5f

Course Resources:
掌握 JavaScript 前端开发，并搭建自己的APP项目
https://www.udemy.com/course/bittiger-javascript/learn/lecture/11069982#overview