Here is a basic square with 0.020" offset for a 0.040" kerf with comments for each line. It's set nice and slow so you can follow it easily as it runs. I left out the corner arcs and leadin/outs so it's super easy to follow.

N100 G20 (Units: Inches)
N110 G53 G90 G40 (Setup no offsets, absolute, no comp)
N120 M06 T1 F20 (Plasma - outside profile, 20 ipm)
N130 G00 Z2.500 (Rapid Z to safe height 2.5")
N140 X2.02 Y-0.02 (Rapid to start point)
N150 Z0.500 (Rapid to pierce height .5")
N160 M03 (Start torch)
N170 G04 P2. (2 second pierce pause)
N180 G01 Z0.100 (Feed to cut height .1")
N190 X-.02 (First side)
N200 Y2.02 (Next)
N210 X2.02 (Next)
N220 Y-0.020 (Next)
N230 M05 (Stop torch)
N240 G04 P1. (Pause for post flow 1 second)
N250 G00 Z2.500 (Rapid Z to safe height)
N260 X0.000 Y0.000 (Rapid to home)
N270 M30 (End program)