Domain Name Enter the website domain name without the leading www.
PHP Version It's recommended to either use the default version (listed above) or the very latest version (highest number) if that works for your website. Only use an older version if you absolutely must do so to make your website code work.
Username By default this should be left blank which will create a new (unique) username just for this site. Optionally you can pick from a list of existing users, or first go to the User admin and create a specific username & password.