How do I create a Client Logos section in admin menu?

This would probably best be solved with a custom post type for the Exhibit.

That will give you a new section in the admin-area with posts/pages for each exhibitor.
That way you can for example use:

• Post thumbnail as “exhibitor_logo_img”

• The post title as “exhibitor_title”

• The content area as “exhibitor_bio”

• And if you need the “exhibitor_id” separate from the content, that could be done with a custom field named “exhibitor_id”.

Have a look in the WordPress codex for info on how to setup a custom post type.

Or if you prefer a more graphical way of doing it, you can also do the same with a plugin. There are several plugins that handles the setup. Such as “Custom Post Type UI“.