In the manufacturing environment, the Industrial Internet of Things (IIoT) allows machines, products, and processes to communicate with each other to achieve more efficient production. With the growing move to Industry 4.0, increased digitalization is bringing its own unique challenges and concerns to manufacturing. An important component of meeting those challenges is with the use of a Digital Twin. A digital twin provides a virtual representation of a product, part, system or process that allows you to see how it will perform, sometimes even before it exists. A digital twin of the entire manufacturing facility performs in a virtual world very similar to how the entire manufacturing facility performs in the physical world. This broad definition of a digital twin may seem unattainable, but it is not—advanced discrete event simulation products and modeling techniques now make it possible. This chapter will describe the importance of a digital twin and how data-driven and data-generated models, real-time communication, and integral risk-analysis based on an advanced DES product can solve many of the challenges and help realize the benefits offered by Industry 4.0. We will illustrate by providing a brief tutorial on building a data-generated model using the Simio DES product.