You will add your files to
If you're using other languages such as "js, css" you will create folders under public_html i.e. css, js then place your stylesheet in that folder and link to your website pages.
<link rel="stylesheet" type="text/css" href="cs/mystyle.css" />
You understand now? If still having trouble watch some YouTube videos - http://www.youtube.com/watch?v=GwQMnpUsj8I
Here is a popular tutorial! Have fun designing!