I have used Fluent at my faculty.
CFD simulation is split into two parts. First you have to set up geomety, computing grid and boundry types (eg. wall, air inlet, etc.). So you must learn 3D modeling and gain some knowledge about meaning of different grid setups.
Next step is to load the geometry with computing grid into next program, where you set up simulation. First you have to set boundry conditions, select apropriate models (a lot of them, with a lot of different parameters for each model...) and then you run simulation.
My mentor had to explain me everything a couple of times before i was able to do a simple simulation.
CFD simulation can help you, but of course you should also use some measurments taken of some real model.