Page not found but deployed and published successfully

I’m doing the content management using Notion and deploy the content to Netlify.
The Repository
I got this after I new a website through Netlify using this link:

After the creation of the website, the website has stayed in the status “Page not found” before I changed anything.

Then I change the URL in the example/gatsby_config.js and pushed to the Github, and published the deployment, which is successful. The latest time of the successful publish is exactly the first link.

Then I do the code:

yarn global add gatsby-cli
Gatsby new my-gine-blog
yarn develop

Does anyone know what’s wrong with my files?

I have Yarn, Git, Github Desktop, Gatsby, Node.js in my computer.

The page not found is normally caused by a missing index.html file in the base of the publish directory for the site. You can confirm this by looking at the files in the deployment using the download deploy button. The following screenshot shows this button:

Is there an index.html file in the base directory of the downloaded deploy zip file?