I am following the tutorial on the Simulation of flow around a vehicle. But when I arrived at point 1.3. I got stuck in some problems regarding the marking of the wheels off the vehicle. I can´t mark the wheels and therefore can´t complete or go on with the tutorial.
If I think what you mean is you are having trouble creating topological entity sets and selecting them, I can explain that. First, at the top, there is a bar that has different selection tools. Click the one that shows one red face and select all of the front wheel. Then press the plus button and create a topological entity set with that, then rename it the front wheel. Then repeat the process for the back wheel and the body of the car.
Hope that helps and have a great day,