may be not a tool.
what you need is a Method Of Work.
the first step is WBS. which means work breakdown structure (WBS), in project management and systems engineering, is a deliverable oriented decomposition of a project into smaller components. It defines and groups a project's discrete work elements in a way that helps organize and define the total work scope of the project.
The second step is to allocate the resources. You should, you need business analyst, chief architect, develpers, testers. You also need the hardwares, iphone, mbr, etc. You need an office.
The third step, when devs+QAs is avaialbe, they need to set up the work env.
Then technical selection. To choose the correct or appropiate technical skill set for your product.
Then demostration to your customers and get feedbacks from them.
Change your product design and implementation according to the feedbacks you collected.
then demo->change-->demo-->change..... .....