What commands do I need to know to switch cameras using the multi camera doubleplexer stereo module

Raspberry Pi Zero W
Doubleplexer stereo module
Two V2.1 camera modules

I want to know the commands needed to switch between the cameras on the command line. I also want to know the commands to take a picture and capture an video.

If there are any useful links and webpages that describe what I am looking for I would be greatful

Is anyone able to help?

There are two guides

You need to use a script to change the camera but can use standard Raspberry Pi commands to capture the photo or video