This lesson covers the process of defining the domain of a boundary value problem, specifically focusing on the fluid region inside the artery using Ansys Workbench™ simulation integration platform. The lesson guides through the steps of importing the necessary geometry file, viewing and verifying the imported geometry, and setting up the locations for applying desired boundary conditions. The lesson also explains how to use the named selection tool to define inlets, outlets, and the outer walls of the artery. Finally, the lesson concludes with saving the project in a desired location.