Clarify My Project Scope

I have an early-stage idea—currently summed up only by the working title “Wkwkkwwwkwk”—and I need help turning it into a clearly defined project brief. Right now, the format (website, app, or something else), the core objective, and the exact audience are still open questions... (Budget: $250 - $750 USD, Jobs: Agile Development, Business Analysis, Business Strategy, Content Strategy, Digital Product Design, Product Management, Project Management, User Experience Research)