Carla midi plugin control

Hello guys.
Just started playing with jack today. I am using carla at this time.

My wish is to setup a way to send commands to events-in in my patchbay. My understanding of how to do that is with midi. This leads to my problem which may just be my inexperience with midi since I have never tried to do anything with midi until today. I am completely unsure how to structure a command which would change the for example the Audio Gain (Stereo) gain level.

I was trying to use amidi -p(my midi device hw:6,0 or something) -S 'B1 01 00' I think this was the layout? B1 being channel 1 I think hesitantly. 01 being the midi control I want. at least i think. And then 00 just being the value to set the gain to. At least this is all what I thought which appears to be wrong since nothing was managed to work.

A screenshot of the audio gain plugin.

A screenshot of that section of my patchbay

If someone could help I would greatly appreciate it.