This tutorial will describe the fundamental technologies, terms and concepts associated with Modeling and Simulation (M&S) and describe M&S development and application in the Department of Defense (DoD). The tutorial will cover various aspects of M&S including key M&S terms and concepts that describe M&S technology, development, and application. It will include: (a) M&S terminology and concepts used in the Department of Defense (DoD); (b) M&S technology, architectures and interoperability protocols and their role in enabling key functions in the DoD; (c) The processes for developing valid representations of: DoD warfighting capabilities, threat capabilities, natural environment, complex systems, cyber, autonomy, artificial intelligence/machine learning, and human and organizational behavior. The attendee will become familiar with how M&S is used in the DoD for operational purposes - especially training and other areas of direct warfighter support; and the DoD M&S role in enabling key functions of the Department. This tutorial will identify key policies and procedures for DoD M&S, and present the critical role of Verification, Validation and Accreditation (VV&A) in ensuring that models and simulations meet the needs of their users. The tutorial will present the role of M&S Standards in the Defense Standardization Program, its role within the DoD M&S framework, and its impact in DoD M&S use. The tutorial will describe the characteristics and associated challenges of M&S applications within DoD functional areas including: Training, Analysis, Acquisition, Test and Evaluation, Experimentation, Planning, Medical, Mission Engineering, Autonomy, DoD Research and Development/Employment, and Intelligence. The tutorial will also identify accessible DoD M&S information resources and explain the role of the USD (R&E) DMSCO as the focal point of DoD M&S information, practice, technology, and functional use.