Mobile app onboarding design

We are preparing to launch a mobile app and want to commission the full onboarding design — the very first journey a person takes right after installing. It matters to us that a new user understands within a minute why we exist and reaches a first tangible benefit without any friction. We need welcome screens that show the key capabilities, a sign-up flow broken into short and obvious steps, and a careful permission request for notifications, location and camera that always explains why we ask before the system dialog appears. Most of all we need a well-designed first-value moment, the point where the user quietly thinks, yes, this actually works for me. We expect a coherent scenario rather than a folder of pretty pictures: the logic of transitions, empty and error states, the wording of hints, and graceful handling of refusals. Please deliver a clickable prototype, layouts for both iOS and Android, all states laid out, and a clean developer handoff with spacing, type and components documented. Tell us how you will reduce drop-off at each step and how you will measure success. Our audience is ordinary people, not engineers, so clarity and trust matter more than trendy tricks. Share similar work and propose a week-by-week plan.