I will use realistic N-body chemo-dynamic simulations to provide understanding about the formation and evolution of galactic discs and of their structures. After a general introduction, I will focus on a few specific points, as e.g. the influence of bars, a comparison of the evolution and properties of the thin and the thick discs, etc. My approach will include not only morphology, kinematics and dynamics, but also stellar populations, defined by their ages and chemical abundances. I will, whenever possible, make comparisons with the Milky Way.