This starter build MDX support into the gatsby-default-starter. Its README also applies here.
- Create a new Gatsby site using this starter
gatsby new my-site https://github.com/gatsbyjs/gatsby-starter-mdx-basic
- Install dependencies
npm install
- Run the develop script
gatsby develop
- Edit Page 2 in
src/pages/page-2.mdx
Deploy this starter with one click on Gatsby Cloud: