I need an Arduino guru to help me write and understand code

Building an arduino controlled lawn mower, I took two 24 volt motors from a jazzy pride wheel chair. welded a frame for my lawnmower with front caster wheels. for the motor controller im using a Cytron mdd10a to Cytron CT-uno with cytron ps2 shield.
what I would like to do is be able to control the unit by either joysticks or R1,R2,L1,L2
From my basic understanding with the mdd10a that it would have to be controled via pwm