The systems approach provides a set of categories for thinking about business. Inputs, outputs, etc. These are abstract categories, not concrete. Typically inputs are resources and demands on the system.
Outputs are goods and services, decisions of the system.
The system approach also gives you a set of considerations or perspectives. Ways for thinking about organizations. There is interdependence or contingency among the categories. Inputs are transformed into outputs. Outputs are contingent on the inputs and the transformation process.