would somebody like to help with a program to make a submarine?

OK john here is what I have.

The input coming in I can see and now what I need to do is figure out how to get the output of pins 9 and 10 for pulse width modulation. and I would like to set my limits. Then make it so that outputs 2 and 4 cannot be turn on at the same time. Is possible that is in the code already. I have tried the wii chuck library's and they are not working. I don't know enough to change them to make them work. I know the bare minimum to be dangerous.
To make things easier would it be easier to make the forward position to be fixed and when the x joystick is met to the min threshold then one of the motors will shut off and the other will come on. Instead of trying to make then speed controllers. just make it a fixed speed. That I could change with the PWM if I need too.