The first is really simple, go to file manager of cPanel. Browse to the folder where your files are.
Create a new file called index.htm (or upload one from your computer).
The index doesn't have to contain much data, though a small information and a link to the homepage of your site could be a good idea.
This is a basic html skeleton:
Code:
<html>
<head>
<title>The name of your site here</title>
</head>
<body>
<div style="margin:60px auto;width:60%">
A little information here
<a href="http://www.domain.com">Startpage</a>
</div>
</body>
</html>
The <div style="..."> is optional, but places the text a bit down from the top of the page and also puts it more to the center of the page side wise. Remember to remove the ending </div> as well if you remove that part.
The red text is the one you should change to match your site.