There are a couple ways to do this, the easiest would be to use FTP (File Transfer Protocol) to add your content into your public_HTML folder, which is where your web content is served from.
Download a FTP client, like FileZilla, or you can use the built in File Manager in cPanel to upload your files to the correct directory. Ensure that you have the correct file structure in place, or some links may not work correctly.
In your welcome email when you sign up you will find your FTP username and password, and some basic instructions on how to use FTP.
Qouted from Afriman