I have no idea whats inside your machine, maybe somebody will help there. But basically you rip out the main board fit the new one inside or make a separate housing, read the manual of the new board, connect the stepper drives to the board, connect limit switches, connect buttons to inputs, map inputs in Mach 3.
You will need Mach3 also. That's the program that most people use for CNC, its inexpensive , has great forum, ...



If nobody knows more details, basically i will help you. You will need to open the machine control box? and take some pictures, of the board, drives and motors.