I bought 2 MD30C motor controllers. I was unaware that it was required to press either A or B to operate this motor controller. What do I need to do to be able to run it without having to press the switch. The video at the on the webpage shows it running with something hooked up to it. I need two of those. Thank you in advance for any help.
Hi there @CleanerExhaust and welcome to the forum!
If you want to use the motor controller in standalone mode you will have to press the switch but if you want to operate it using a microcontroller like an Arduino you can follow this tutorial:
I think the video you watched is from this tutorial:
https://www.instructables.com/lesson/Controlling-Motor-Speed/
You can find the Arduino libraries for controlling the MD30C here:
I hope that information can help you out 
That is all above my pay grade. I will look for a controller that can operate stand-alone.