Someone says design a PCB, you'll think of an engineer opening up a datasheet, looking at the application notes, picking their components and starting the process of assembling a schematic, aka the behavioural arrangement of how all these components connect to each other [cont.] Once behaviour has been grouped and assigned hierarchy (e.g. power, connectors, etc.) you have a schematic ready to be turned into a netlist. This netlist contains all the connections of the components, the wires between components as well as description of behaviour. [cont.]