You must know who you are, before you can broadcast it to others. He cites examples. Weapons are metaphors for, or extensions of, men throwing rocks. Computers are metaphors for books and libraries. The Viking probe on Mars is a metaphor for the dream of touching another world.
People are metaphors.
You can describe them quite easily. In this context the author said Newhall must find its metaphor. We discussed Newhall's western heritage. Its Walk of Western Stars. Tom Mix and Gene Autry and Bill Hart.