Know before you go.
Mach is a software interface which provides movement instructions to the drivers based on the instructions given to it.
Gcode are the instructions which Mach needs. You'll need program software ( CAD / CAM ...unless you are going to program manually) to create the gcode based on how you want to cut somthing.
There is more to all this than just plug and play. Enjoy the learning curve.
RICH