Defence against drones and UAS (C-UAS) is rapidly evolving. Every year, there are tens of new C-UAS solutions based on different detection or elimination methods. To effectively test new concepts for using the Counter-UAS systems, researchers need to follow baseline guidance rules for modelling and simulation of such systems. At certain point, they also need to test and simulate tactical procedures and basic command and control processes like identification, fire distribution, and others. This paper brings guidelines and aspects of C-UAS modelling and simulation based on ongoing research at University of Defence, Czechia.