Navigation should reflect the user's mental model of the information. Use a hierarchy when people move from broad categories to detail, peer destinations when several top-level areas have equal importance, and temporary presentation when a short task should not change the user's place. Each screen needs a recognizable destination, a clear way back, and a small set of next actions. Preserve location and unfinished state when users switch sections. Favor established iOS controls and gestures because their behavior is already learned, but validate the structure with realistic tasks: users should reach important content without guessing, unnecessary detours, or multiple conflicting routes to the same state.