How to program MegaMotor Arduino Shield

Hi everyone,
I and really new to programing with C.

I am using 2 megamotor shields to control a electronic wheelchair that i got off Craigslist and have fixed up. Before i was using Pololu motor controllers with the Arduino and it worked but couldn't handle the amount of amperage coming from the two car batteries and turned into flames. I have switched to the megamotor shields but i don't fully under how they function when it comes to programing. For now i just need to be able to make them move forward and backwards at a certain speed.

Here is the user manual:

Thanks in advance

How have you positioned the jumpers for PWMA and PWMB? What they are doing is defining what pin is used to control the speed of the motor(s).

How have you positioned the Enable jumpers? That defines which pin(s) make the motor(s) move forwards or backwards.