This lecture introduces the Cell Transmission Model (CTM) as a numerical method to solve the kinematic wave equation in traffic flow modeling. It covers the fundamental diagram of traffic engineering, calibration, demand and supply capacities, spatial and temporal modeling, macroscopic traffic variables, motorway structure, partitioning into cells, flow conservation, inter-cell flow, and an overview of CTM. The CTM is explained in detail, including the flow-density relationship, flow conservation equations, and the fundamental diagram for each cell.