When you login to your FTP account, you will see 5 folders (tmp, mail, public_html, public_ftp and www). You need to upload all your files to the "public_ftp directory”. Make sure your main page is called "index.php" (as this will be the first page people see when they put your domain name in the URL).
The file needs to be in all lowercase letters. It cannot be named "INDEX.PHP" or "Index.htm" or "Index.html" After you've uploaded your files, you can access your website with the temporary URL which was given in your "Account Setup" letter until your domain name is transferred to us. After your domain name points to our DNS nameservers/numbers, you can access your website with your domain name.