The final step is to write your product specifications, which are the detailed descriptions of your product features and requirements based on your validated assumptions and hypotheses. You need to write your product specifications in a clear, consistent, and comprehensive way, using tools and formats such as user stories, acceptance criteria, wireframes, mockups, flow diagrams, or technical documentation. You also need to align your product specifications with your product vision, strategy, and roadmap, and collaborate with your stakeholders, such as developers, designers, testers, or customers.
By validating your product assumptions and hypotheses before writing specifications, you can increase your confidence and credibility in your product decisions, reduce your risks and uncertainties, and deliver more value and satisfaction to your customers and users.