Fusion Template
In the Moehaha.com WHMCS reference implementation we use the Fusion template from TemplateGenie.
Acquire and download it from their website: http://www.templategenie.com/templates/whmcs/fusion/
Follow the installation instructions provided by TemplateGenie.
Next
You will now want to install the OAuth 2.0 Add-on Module in order to integrate with ItsYou.online for authentication.