When you start FileMaker Go on iPhone you will see choices for opening Apps that are pre-installed or that you have added. One choice is My Apps in the lower left where you can choose the Location, On My iPhone, and see Apps in a list or buttons.
Tap a pre-installed example like Invoices to see how this works. Without sample data, you would need to create a Customer and a Product before you Create New Invoice. However, the point is to look at the tools that could be arranged to suit your needs.