By now, you've seen the site map and the emerging visual design for the new site; these are like the foundation and the décor of a new house. Between these two layers, there's a lot of design work around creating the rooms, placing the windows, planning the traffic flow, etc. In a website project, that design work is represented in mockups or wireframes that define how the pages will be laid out, what content will be presented, and how the navigation will work.
The 30+ mockups in this PDF cover a representative set of page templates to allow Drupal development and content creation to begin. The designs are based on the user data we collected, and have been validated at several stages by user testing and reviews. We'll continue to validate (and modify) these designs as we build them into a functional site.