Now that you’ve hired a developer, here’s what he should do first…
Develop the User Interface
For the first milestone have your developer build the UI based off of your concept.
Have them build out the entire user flow as a clickable (tap-able) prototype that you can test on your device before they begin coding the core functionality.
This way you’ll get a feel for how the app will behave and whether or not it meets you and your potential users expectations.
It should be intuitive and easy to use.
If it isn’t, this is the time to work with the developer to fine tune it.
It is critical that get this part right up front! Why?
Because after the major functionality has been coded, it will become increasingly more difficult, costly and time consuming to make changes.
This will cause the project to go over budget and over time.
After you’re satisfied with the overall user experience you’ll want to continually and regularly test your app throughout the development process.