Petri Net, a widely studied mathematical formalism, is a graphical notation for modeling systems. Petri Nets provide the foundation for modeling concurrency, communication, synchronization, and resource sharing constraints that are inherent to many systems. However, Petri Nets do not scale well when it comes to modeling and simulating large systems. Colored Petri Nets (CPNs) extend Petri Nets with a high level programming language, making them more suitable for modeling large systems. The CPN language allows the creation of models as a set of modules in a hierarchical manner and permits both timed and untimed models. Untimed models are used to validate the logical correctness of a system, whereas timed models are used to evaluate performance. This tutorial introduces the reader to the vocabulary and constructs of both Petri Nets and CPNs and illustrates the use of CPN Tools in creating and simulating models by means of familiar simple examples.