how to enter 3 timing pulley?

can some one teach me how to input the gear ratio.
24 tooth pinion attach to stepper motor
and 72 and 24tooth on a common shaft.
24 tooth pinion drives the 72 tooth gear and 24tooth gears meshes with the rack
gears.the pitch of the rack =3mm.
So how can i put the gear ratio to the axis configuration?
motor steps per rev.=200
driver microstepping=4
pulley teeth=24,and 72,and 24 teeth where can i put it.

you can simply calculate your Steps per Unit
and give it the way you need aying 100steps/mm =0,01mm/step
is 200Motor Halfstepping 2 =400 no gear Pitch 4mm = 100 SCALE DONE
-> pitch 3mm 400steps = 133,33steps per mm -> 200Motor Halfstepping 2 =400 NO gear entry pitch 3mm

YOU SEE THE NUMBER ON THE SCREEN

Meaning in the Frame almost Down is the SCALE visible so take the numbers to your need
make a Image so wa see how the Gear is connected to the Rack and we calculate the input numbers

1 rotation of the pinion is 24x3 = 72mm
you have a 1:3 gearbox so divide that by 3 and you get 24mm for one motor revolution
now divide that by the microstepping if you are using it and use that value.

this woudt be a scale of 11.11111