The document discusses the importance of prototyping simulations early and often. It recommends following an iterative process of prototyping, testing, gathering feedback, and refining. Specifically, it recommends: - Prototyping fundamental game design, user interface, mechanics, and learning objectives early with designers, subject matter experts, and potential users - Testing prototypes on the intended audience and refining based on their feedback before final development - Continually refining the simulation based on new playtests to ensure it meets learning objectives and provides a high-quality user experience