Well, ducking is automatic by nature. The whole idea is that it listens to the primary source and when sound found above the treshold level, brings down all other sounds.
So, if you press the ducking button, from that moment on it will “listen” on the mic and if there is an input above the treshold it will cut down the level of all else. Clearly you don’t want that to happen when the mic is laying next to the mixer/player and picking up crowd and PA sound. Hence the on/off button, so it is only active when you want to use the mic for talking.
There is, far as I know, no controls to set. It’s all fixed for the parameters you mentioned.
Being an old hand from the days before auto anything, I was (and still am) used to just riding the faders. That way you have full control over timing and levels. For my personal taste ducking on most controllers/mixers takes the sound away too much. I like it to have my voice just slightly above the music, keeping the overall energy levels about the same to prevent it from sounding like a break/pause in the music.
Making a video seems like a waste of time as all it would show is what happens when you press the ducking button. Easy enough to check for yourself .