Designing for NAV requires more forethought and knowledge of the operating details of the application than was needed with traditional models of ERP systems. As we have seen, NAV has unique data structure tools (SIFT and FlowFields), quite a number of NAV-specific functions that make it easier to program business applications, and a software data structure (journal, ledger, and so on) that is inherently an accounting data structure. The learning curve to become an expert in the way NAV works is not easy. NAV has a unique structure and the primary documentation from Microsoft is limited to the embedded Help, which improves with every release of the product. The NAV books published by Packt can be of great help, as are the NAV Development Team blogs, the blogs from various NAV experts around the work, and the NAV forums that were mentioned earlier.