In the field of particle technology hydrodynamic modelling in the form of CFD or DEM is an area with increasing focus in terms of modelling approach to granulation processes. Although being used at many universities and in industry it is a difficult topic with only few textbooks available. This text provides a beginners guide to hydrodynamic modelling with focus on agglomeration processes. The basic terms and principles are introduced including Eulerian and Langrangian models. Thus, you will be familiar with the basic principles and theory within this interesting field on a bachelor or master-of-science level.