A panel structure with a slotted mounting system includes: a first post; a second post; and a panel that is configured to be mounted to the first post and the second post. Each post includes one or more fasteners that extend outwardly from a body of the respective posts and can be loosened to define a shelf on which the panel can be hung. The panel includes slots corresponding to and configured to receive the fasteners extending from the body of the first post and the second post. Once hung, the panel is released, and the respective fasteners of the first post and the second post tightened to impose a clamping force to secure the panel. The panel structure can include a plurality of posts with fasteners and a plurality of panels with slots corresponding to the fasteners of the respective posts to provide a multi-walled structure when assembled.