You may upload a website using any FTP client.
If you are on a Mac you can use: CyberDuck (free), Fetch, Transmit, etc.
On Windows you can use: CoreFTP (free and paid versions), TangoFTP, FileZilla (free), WS FTP, etc.
The settings to connect to the server are as follows:
FTP server: smallgod.net
Username: Your "FTP Username" as setup in the control panel under Websites & Domains > FTP Access.
Password: Your "FTP Password" as setup in the control panel under Websites & Domains > FTP Access.
Path/web root directory: /httpdocs