It is important to understand that the Generic App serves two distinct purposes: as a starting point for the development of custom webs, and as a vehicle for building and proofing the database content. Since the core mechanisms remain the same the processes of building content and refining functionality can proceed in parallel. In a real project the steps defined in this chapter need not be be executed in the order stated, and redefinition and rebuilding multiple times to get the desired end result are to be expected.
This will make more sense when you've built the sample, or just reviewed this part of the document.