For every scientist and also for engineers, knowledge of computational methods and the capability of writing his or her own simulation tools are very important and have become everyday tools in science, research and development. Programming skills are not required for this course and will be developed during the lecture as necessary. We will develop code examples in the high-level language C. Learning by doing applies! Important basic data structures and algorithms will also be introduced. Rather than being occupied with where to click buttons in a commercial or academic black-box program, we will discuss the inner workings of a functioning scientific Molecular Dynamics / Monte Carlo program. The students will learn how to plan, organize and write their own simulation code from scratch. The presented simulation approach is based mostly on classical coarse-grained models of fluids and macromolecules which allow for covering much larger length and time scales than is possible in atomistic or electronic structure simulations. However, we will also cover to some extend classical atomistic MD.