When I open my project in this it showing 404 error. How can I publish my project?

I can’t see your repository (I assume it’s private), so it’s impossible to say. A common issue is that the project is lacking an index.html file.

I made my repository to public. But still it’s not running.

No, making the repository public won’t make it work, but it lets people here take a look to see what might be wrong. :wink: