See also: Transformation Analysis
Transformation calculations are demand-driven. That is, each module is operated to meet the demands that arise from domestic requirements and export demands (net of any minimum specified level of imports). For the first calculated module (the one closest to demands), domestic requirements are set equal to final demands (see Demand Calculations). After each module is calculated, domestic requirements are decremented by the outputs produced from the module, but incremented by the input fuels required by the module. Ultimately the calculation yields the requirements for primary resources (fossil and renewable), which can be compared to the amounts specified in your Resource branches.
Note that the ordering of modules will effect calculation results. Before calculating make sure you modules are in the correct order in the tree. (e.g., an electric transmission & distribution module should lie above an electric generation module).