Here is the Mach3 manual:
Page 3-7 has some simple code to input to see what happens. Don't forget to zero all the azis before you run the code. Don't ask me how I learned this.
Go to the Mach3 homepage:
and click on Tutorials and then Video Tutorials. Start at the top and work your way down. There is a wealth of information in there. You will learn how to zero the axis.
You will spend some time reading, searching, and studying to make any sense of this. I spent about a year researching CNC mills before I actually took the plunge and then it was only because to CNC my mill was only a few hundred dollars more than a DRO and powerfeed which I originally wanted. I am going to be MUCH happier with the CNC. I can already tell.
You *should* be able to start the motors by just pressing the arrow keys. That is if all the settings are correct in Mach3.
I am totally new at this too, but I'll tell you what I can and show you what I can based on my learning cycle.