I'm a bit confused
Your index should be a file, not a folder. The file named "index" in a folder is the home page. So when people type in your domain, they're taken to the file named "index" that is in your public_HTML folder. If the index is in another folder inside public_HTML, then they'd have to type yourdomain.com/foldername/index.html to get to it - do you understand?
So, try moving your files out of the folder and straight into public_HTML.