Hi Jim, welcome to the group.
I suggest that you first take some time and familiarize yourself with the Install Manual.
http://www.machsupport.com/docs/Mach3Mill_Install_Config.pdfIt does a very good job of walking you through the basics and is sure to get you going in the right direction.
It is a valuable resource. Of course, if you have trouble understanding anything there, folks here on the forum will be glad to help.
Regards,
Russ