The "Content" means the unit for delivery.
The "Resource" means the data such as documents, images, and videos, that are used to create contents.
A content is made of a base PDF file, and images and videos that are overlaid on the base file.
For your help, a .zip file has a similar structure as a content of SMART CATALOG.
The "Content" is compared to a .zip file. And PDF file, images, and videos are compared to the components of the .zip file.
The application shows the "Contents".