That is done by your steps per unit in Motor Tuning. You work out how many steps it will take to move the axis 1 unit, for example 200 steps for stepper x 10 microsteps of drive x 2 for gearing would equal 4000 steps per 1 rev of screw. If your screw was 10 tpi then it would need 10 turns of screw to move 1 inch so the previous number would be multiplied by 10 to give you the steps per inch, 40,000 in this example.
Hood