Let's say that we have a React app. I am going to use the starter app provided by React. You are free to try this out in your more complex app. The steps for doing so are going to be exactly the same.
Integrating Web Components in React
Setting up a React project
If you have your own app, you do not need to go through this section.
You can use the following link to set up the project: https://facebook.github.io/create-react-app/.
Once the setup is done, you will be left with a project that can be run using the following command:
npm start