The document discusses designing interfaces for mobile experiences across different screens and platforms. It recommends taking a user-centered and service design approach to create a blueprint of the whole experience before designing interfaces for specific channels. The blueprint involves gathering information, defining personas and goals, listing all possible features, filtering to only necessary features, grouping by dependencies and priorities, and arranging notional interfaces. Interaction designs and interfaces can then be created for each channel by further filtering the blueprint and optimizing for interactions and interfaces on that platform. Communication and buy-in are also discussed as important to the design process.