Paul Scanlon provides a detailed guide on migrating from Netlify Functions to Gatsby Functions, emphasizing the advantages of using Gatsby Cloud's built-in serverless functions available since version 3.7. The process involves upgrading to at least Gatsby v3.7, removing Netlify-specific plugins and configurations from gatsby-config.js and netlify.toml, relocating function files to the src/api directory, and refactoring them to use Gatsby's "express-like" syntax. Additionally, client-side requests should be updated to reflect the new path structure starting with /api/, and any Netlify-specific scripts should be removed from package.json. Scanlon also offers resources such as a demo repository and an invitation to connect for further information on Twitter.