Modelling of general systems is a way of describing how things work by using simple drawings and diagrams. It's like using a picture or map to show how different parts of something come together to make a whole. For example, a car has four wheels, brakes, an engine and other parts. We can draw a simple diagram to show how those different parts fit together to make a working car. We can also use modelling to show how the parts interact, like how the brake pads help the car slow down when you step on the brakes. By modelling general systems, we can understand how things work much better.