Control DC by 4 Mosfet

I am planning using 4 Mosfets to control a DC motor (27V, 5 A). I want to use the pot to control. When I set the pot in the middle, the motor should stop, turn to the left the motor run foward, and turn to the right, the motor turn backward. I don't known how to code it. Any one please help!
Thanks a lot

Start by reading up on H Bridges to understand how to make the motor run forward & backward to start.
Then it is not much more of a step to control the H bridge by reading pot & creating the appropriate H-bridge control based on the analog read (0-1023) of the pot voltage from 0-5V.