SD-WAN

I am unable to find any options for SD-WAN in our Fortigates. I have seen that is should be an option under network, but it doesn't appear there. I have found in the FortiCloud account that SD-WAN is disabled, however, I cannot find where to enable it. I have found the configuration for SD-WAN in CLI, but no where to enable the option to configure in the GUI. 

How do I go about viewing the SD-WAN options in the GUI, and/or is it an issue where there is additional licensing cost for the SD-WAN features and is that the issue that is preventing it from showing up on the firewalls? We are running 6.4.8 currently. 

Thanks