This tutorial will identify and explore the essential techniques necessary for modern military training simulations. It will provide a brief historical introduction followed by discussions of system architecture; simulation interoperability; event and time management; distributed simulation; and verification, validation, and accreditation. This will be followed by fundamental principles in modeling and specific military modeling domains. The growth in government sponsored simulation programs has drawn engineers and scientists from other fields. These practitioners bring valuable skills, but lack an appreciation for the historical and technical foundations of simulation. The tutorial will familiarize the audience with important areas and give them an appreciation for the complexity of developing large simulations. We suggest that a need exists for academic and commercial courses that focus on this topic. This tutorial may serve as a template for one such course.