Directory structure
You probably started with the Gatsby Blog Starter Kit. It puts each entry in its own directory, but that’s not at all required. It would be equivalent to name each markdown file with the path you’d like.
But really, you probably don’t want your project directory structure dictated by the URLs you’d like to surface to the web. That’s where the path frontmatter property comes in. You can give a file whatever URL you want! The only real requirement is that it’s a file Gatsby understands under the pages directory.
https://blog.scottnonnenberg.com/practical-gatsby-js/