Question about my Sketch.

OmegaRa:
seem right for this section of code?
Here is a quick attempt at adding the Right pins and void setup, a little confused as to where to put stuff in the loop...

void setup()   // This runs once when you power up or reset 

{
 pinMode(LEFT_MOTOR, OUTPUT);  
 pinMode(LEFT_BRAKE, OUTPUT);
 leftMotor( FORWARD, FULLSPEED);   // *** don't need this here
 pinMode(RIGHT_MOTOR, OUTPUT);
 pinMode(RIGHT_BRAKE, OUTPUT);
 rightMotor( FORWARD, FULLSPEED);  // *** don't need this here
 
void loop()   // This one loops over and over
{
 leftMotor( FORWARD, FULLSPEED);
 delay( 4000);   // on and off every 4 seconds
 leftMotor( FORWARD, 0 );
 delay( 4000);
}  // it goes from here back to the start of loop instantly

I would recommend removing the indicated *** lines in setup, Compile and run, the motor should go on 4 seconds and then off 4 seconds, on 4, off 4. Then in loop() just change the leftMotors()s to rightMotor(). You're just making sure the motor works here.
Also see if you can add the lines in the loop, to test the reverse:
right fwd full
delay
right fwd 0 (stop)
delay
right reverse full
delay

Modify for both motors fwd, 1 fwd 1 reverse, half speed (128), etc.

Make sure you understand the concept that setup runs once, first-- and loop then runs forever, over and over.

Cheers,
John