In QuickBooks you assemble an item by issuing a "Build". This is a process by which the program will take the component list for an inventory assembly, decrement the appropriate quantity of each component, and increase the quantity of the inventory assembly itself. QuickBooks itself can only perform a "single level" build, just issuing the first level components of the inventory assembly. CCRQBOM can also perform a "multiple level" build, where a build is issued for the inventory assembly, and if any components are themselves inventory assemblies then an additional build is issued for that assembly.