Need some hint how i start to c code of this system [on hold]

I am creating a closed loop system with a MAF sensnor DC motor and PIC18F4520 I require a short code in C so my sensor can send a voltgae signal to my PIC18F4520 the PIC controller need to control a motor via a SN75441One motor driver. * If the voltage is between 2 and 4V the output of the motor should remain the same and an LED on Port C should light up * if the voltage is below 2V the motor control should increase speed and different LED from port C. 8 if the voltage is above 4V the motor control should decease speed and different LED from port C.