Download the example or clone the repo:
curl https://codeload.github.com/mui/material-ui/tar.gz/master | tar -xz --strip=2 material-ui-master/examples/create-react-app-with-styled-components
cd create-react-app-with-styled-components
Install it and run:
npm install
npm start
Note that CodeSandbox is not supporting react-app-rewired, yet you can still see the code.
The following link leverages this demo: https://mui.com/guides/interoperability/#change-the-default-styled-engine with Parcel's alias feature within the package.json
This example demonstrates how you can setup Create React App with styled-components as a style engine for your application.
You now have a working example project. You can head back to the documentation, continuing browsing it from the templates section.