Okay. If you don't know how to use a browser,
you should'nt try coding. Sorry to say that.
localhost seems weird anyway. Even if you're using XAMPP for "whatever your try to do there", then you have a folder of your stuff on your local machine. So even C:\\myfolderwithmyxammpproject\public\index.html and C:\\myfolderwithmyxammpproject\public\css\style.css should return anything.
If it's on a real server than it's also not localhost. It's your domain, or your domains IP. If you don't know waht im talking about at all than read second line of this answer.
This forum isn't supposed to teach people from the scratch. We help solvings problems. But where should i start help you changing a tire if you don't even know how to open your trunk?
Sorry.