gatsby-shahcoals | Gatsby Plugged-In in Existing in React Application

Use the Gatsby CLI to create a new site, specifying the hello-world starter. Navigate into your new site’s directory and start it up.
Create a Gatsby site. Use the Gatsby CLI to create a new site, specifying the hello-world starter. # create a new Gatsby site using the hello-world starter gatsby new my-hello-world-starter https://github.com/gatsbyjs/gatsby-starter-hello-world
Start developing. Navigate into your new site’s directory and start it up. cd my-hello-world-starter/ gatsby develop
Open the source code and start editing! Your site is now running at http://localhost:8000! Note: You'll also see a second link: http://localhost:8000/___graphql. This is a tool you can use to experiment with querying your data. Learn more about using this tool in the Gatsby tutorial. Open the my-hello-world-starter directory in your code editor of choice and edit src/pages/index.js. Save your changes and the browser will update in real time!