This document discusses digital prototyping and usability testing. It recommends: 1) Choosing a digital design and prototyping tool to create high-fidelity wireframes and prototypes based on customer journeys and paper prototypes. 2) Conducting usability testing on prototypes with 5 users to validate the design through observational testing and 5-second tests, and collecting feedback to improve the prototype. 3) Iteratively testing prototypes with users and making changes based on their feedback to create the best possible design.