First, use the Configuration Helper to generate a basic Data Entry Definition. The important part here is to have it fill the list of fields.
The data entry definition stores data in a relational database, to multiple tables, but it is flat itself. This means that you can't enter one vehicle after another until you're done. The data entry definition may contain entry fields for as many vehicles as you like, but that is exactly how many may be entered. Therefore there need to be fields such as "VehicleDirection1", "VehicleDirection2", "VehicleDirection3", etc.
