Control the PWM signal entering each motor

First of all, I’m a beginner
And I’m using Ubuntu 20.04
I’m trying to use iris.

make px4_sitl gazebo
When I do, the iris comes out on the gazette, but what I want is to control each motor of the iris.

I want to turn off the motor and turn it on in real time.

What I know is that it is the PWM signal that activates the motor after all.
I think the last PWM signal goes into each motor. So if I control the PWM signal at the end, I think I can control the motor in the real time I want.

And if I want to use PWM_AUX, can’t I use simulation or can’t I use iris?
As you can see in the picture I attached, I only have SIM. How can I write PWM_AUX tab?