Cross Platform Mobile Soundboard App Requirements and Design

I'm looking for help determining the requirements for and the design of a cross platform mobile application. The basics is a soundboard style application where the user presses a button to hear various sounds. 1. --> Requirements and Design <-- 2. Artwork and Audio 3. Build and Deploy There's a few concepts in mobile apps I think I'd like and I'm sure a number of concepts I don't even know about. For example, notifications, location tracking and which sounds are most popular. Which revenue model is best for my app, purchase or free with in-app content? From a high level I'm sure we'll need. 1. You to interview me on what the app is and how I anticipate customers using it. 2. You to question me on what mobile features, concepts, and facilities I would want. 3. Wire frame screen and application flow. 4. Suggested services to help with analytics and any other feature we'd use.