How many labels or parts are there and look for a few specific ones as well, including the walls.

Middle ear box out of a shoe box

Middle Ear Box Diagram

As many as will help you remember the relative orientation of the middle ear and it’s various parts.
But try for at least 10-12 things to label, like in the example images above. The more the better. How many labels or parts are there and look for a few specific ones as well, including the walls. A “least effort” grade on something is usually a D.