Check your drawing that the X0Y0 is at that point where you want it to start, then when you create the cam file that will be the start point
Once you home your machine if you do, you then move your tool to the start point of your X0Y0 and Zero the dro for X and Y axes this is then you work offset G54 then you set you Z axes the same way to the top of your work piece and Zero that as well, your first line of code will have X0Y0 your startpoint