Machinery's handbook has a list of Gcodes and enough explanation of the whole process to give you a useful foundation.You will need to determine whether you will be working in metric or imperial units and what the axes are designated as.For initial moves you really need to move quite slowly until you are certain that the connections are moving the machine in the direction you expect.Does the machine have a jog facility to allow you to move things from a keyboard or pendant?Maybe talk to the people who assembled the machine and see how they verified that it moved and what units they used to calibrate things.You also need to be reassured that the axes will move at a rate that isn't being held back by one having a much lower speed capability than the other.The description of the machine makes it seem a lot like a lathe or turning centre.