Re: How does this work.
Look at your cPanel -- it has a file manager (in the Files group), and the file manager includes a rudimentary editor if you absolutely have to edit HTML files on the server. (If you're working with raw HTML, it's far, far better to do the editing locally -- including organising your directory structure -- then uploading the files once you've finished.)
If you want to do a sort of WYSIWYG site building, there is RVSiteBuilder on your cPanel as well.
“Beware of bugs in the above code; I have only proved it correct, not tried it.” --Donald Knuth
"It was as if its architects were given a perfectly good hammer and gleefully replied, 'neat! With this hammer, we can build a tool that can pound in nails.'" -- Alex Papadimoulis (on TheDailyWTF.com)