Welcome to another fire fundamentals episode! Today we dig into how to place a fire in a model so results reflect real physics. From plume inputs to FDS burners, we show where HRRPUA, radiative fraction, and D* make or break smoke your calculations. Things considered in this episode: • why defining the design HRR is separate from placing the source • what a flame is and why we cannot resolve its chemistry • plume models compared by inputs: perimeter, Q, Qc • entrainment, virtual origin, and ...