If you want to use the compiled CSS and not customize any colors, text, etc. you can skip to Step 3a.
Most likely you'll want to start using the Sass mixins to customize your app. MDC Sass files are not supported out of the box, since we do not prepend ~ to our module imports. See this Github issue explaining the issue in detail. There is a workaround, but requires some work on your end (we promise it is not too difficult).
To get MDC React Components to work with create-react-app you need to set a SASS_PATH environment variable that points to your node_modules directory. To quickly do this on OS X or Linux enter the following in your command line:
export SASS_PATH=./node_modulesIf you're on Windows use the following:
SET SASS_PATH=.\node_modules