markstk57,
I will assume that by being new to CNC you are meaning that you don't know much or anything about CNC and that you are trying to use Mach3 as your controlling software.
You may want to confirm or explain more about the above.
So I will just say that CNC is not "Plug N Play " and you need to read the manuals for Mach, watch the videos, learn the basics, and know something about the controller you are using. IE; You need to configure Mach to use it based on your machine.
Welcome to the learning curve,
BTW, DO NOT plug or unplug the motors with them powered up......if you don't know what your doing you could end up doing damage!
RICH