Template: Bind DNS Domain -- how to add cname record?

I have a server template made that I want to automatically add a cname to so it will create it for servers using this template (when they are created). I see where to do this in the System Settings/Server Templates/[template name]/Bind DNS Domain module, but am not sure what to write in that single textbox there.

Its quite a bit different than the step by step html form in the “Server Configuration/DNS Records/Create Record of Type: CNAME”