Create new Powerpoint using a PPT Template

I’m making a new Powerpoint presentation within my automation.
I want to use a specific PPT template for that presentation.
I know the “Use Template” attribute in the Activity is just to help the Designer tool provide point-and-click behavior, not specify a template for the new PPT.

How do I make the new PPT use a particular “theme” (PPT Template file) when I create it?