I assume you are trying to add materials to these objects, so that they can be viewed in the Realistic Visual Style or rendered to give a sense of what things will look like if the design were to be built.
For items that are Multi-View Blocks, such as your cabinets and appliances, one way to do so is to edit the View Block that is assigned to the Other view direction (assuming that you want to view the design in "3D" and not in elevation or section). You can determine what View Block(s) is(are) being seen by determining the active Display Representations for Multi-View Blocks in the current Display Configuration for the current View Direction. In the Display Manager, the active Configuration and Set will be shown in bold type. In your file, with the Medium Detail Display Configuration current and a View Direction slightly rotated from SW Isometric, the Model Display Representation Set is active. The only active Display Representation for Multi-View Blocks is the Model Display Representation.

If you edit the Multi-View Block Definition, you can determine the name of the View Block that is being displayed, on the View Blocks tab.

Add an instance of the View Block to your file, off to the side. You can also copy the Multi-View Block off to the side (with the desired Display Configuration and View Direction set) and explode the copy twice to get an instance of the View Block.
You can now edit the View Block in place, and see if it was modeled with elements to which a material can be applied. In the case of the refrigerator block, that was true, and I was able to add materials to elements, then save the changes to the View Block definition. Those changes will then be reflected in the Multi-View Block.

The attached file is a copy of your file, with an instance of the refrigerator View Block to the right of the kitchen area, to which I added materials.
David Koch
AutoCAD Architecture and Revit User
Blog | LinkedIn
