How to add PDF to devices using Apple Configurator 2

How do you add PDF's to a iPad mini (1&2) using Apple Configurator 2?

I have supervised devices that I would like to add PDF's to, the devices are all iPad mini with the latest iOS for that device. I figured it would be possible to load the PDF's into iBooks. However when I try to "add documents" it does not list iBooks as an app to load documents too...