N90 X0.000 Y0.000 F3600.0
N100 G00 X-27.650 Y-78.650 Z3.000
N110 G01 Z-3.000 F1200.0
line N90 is telling it to go back to the machine Zero with a feed rate of 3600 you can just take out the X0 and the Y0 or change the numbers to some where near your work piece is.
line N100 is taking you at rapid speed to the start of your job and line N110 is dropping your Z down to -3mm at the feed rate of 1200. ..Clive