For conceptual design (architectural or high-level), recognize the interface metaphor to use, interaction type(s) to employ, and interface type(s) to follow. For each of these, make sure to describe why you select what you did.

For physical design (detailed), produce prototype. Prototype must closely represent actual user interface, so use software tool (like Word, PowerPoint, Excel, etc) to make it. Describe how prototype follows conceptual design goals.