victorfb:
I understand. so how can I store the directions the car took?
and how can I use the information that I put on the file?
I can only guess. It might be a speadsheet where each column represents a stepper motor function and each row is a pulse applied to a stepping drive motor. The simplest robot vehicle is probably on three wheels. Two opposite each other are independently driven by steppers, thereby enabling them to do the steering, and the third is just a dumb castor. The course and distance is simply two streams of interrelated pulses, which are just numbers on the aforementioned SD card.
(This is the astronomer talking, not the robot car builder....)