tailwind not starting up in react app code example

Example 1: commmand for installing tailwind to react

npm install tailwindcss

Example 2: how to properly install tailwind css in react

"scripts": {
  "start": "npm run watch:css && react-scripts start",
  "build": "npm run watch:css && react-scripts build",
  "test": "react-scripts test",
  "eject": "react-scripts eject",
  "watch:css": "postcss src/assets/tailwind.css -o src/assets/main.css"
}