Building a block theme from scratch requires just three files: style.css, theme.json, and templates/index.html.
In style.css, add your theme headers and include “Update URI: false” to prevent WordPress from checking WordPress.org for theme updates that could overwrite your custom development work.
For theme.json, create a valid JSON object with schema reference and version number. The schema helps your code editor provide autocomplete and error checking while you develop.
Finally, create an empty templates/index.html file. Even though it’s empty, this tells WordPress you have a block theme and enables the site editor. From this foundation, you can build out your entire theme using the visual interface!