Using the Znode Dynamic Schema capabilities you are able to create custom Attributes for your Products in the PIM.

The general process for this is:

1. Define the attributes you need, and decide the attribute type and details.
2. Create the Product Attribute you need, while choosing the correct type. See: Managing Product Attribute
3. Add the Product Attribute to an Existing Product Attribute Group, or create a new Product Attribute Group.  See: Managing Product Attribute Group
4. Then add the Product Attribute Group to an existing Product Attribute Family, or create a new one.  See: Product Attribute Families

Media Custom Groups and Attributes - Where do they show?

PIM > Products > choose a product