This tutorial article, which is extracted from (Wagner 2019), shows how to use UML Class Diagrams and Discrete Event Process Modeling Notation (DPMN) Process Diagrams for making simulation models of business processes with resource-constrained activities based on the DES paradigm of Object Event Modeling and Simulation. In this approach, the state structure of a business system is captured by a UML Class Diagram, which defines the types of objects, events and activities underlying a DPMN Process Diagram, which captures the causal regularities of the system in the form of a set of event rules. DPMN Process Diagrams extend the Event Graphs proposed by Schruben (1983) by adding elements from the Business Process Modeling Notation (BPMN), viz. data objects and activities, and, as its main innovation over BPMN, resource-dependent activity start arrows.