Before solving a CFD problem in Ansys Fluent, it is important to define the problem precisely in order to obtain an accurate solution. All the necessary options required for defining the physics setup for a CFD simulation are included in the Physics Tab of Ansys Fluent user interface. In this lesson, we will present a short demo using an example CFD problem of fluid flow through a duct to demonstrate how to setup the simulation using the different options available in the Physics tab. We will learn how to activate the physics model, how to define material properties and load additional materials from the material database, how to assign materials to different cell zones, and how to set up the boundary conditions with the help of the Quick Property Editor. Finally, we will also obtain a brief overview of post-processing a CFD simulation in Ansys Fluent by generating reports, creating plots, and analyzing the results.