yes there is a motor controller
Ok so look at the pins the motor controller uses and make one motor run. It might/will have an Enable pin, Direction pin and Speed pin. All of which will need to be set properly and defined.
Example:
byte/#Define Enable = 2 //High = allows motors to run
byte/#Define Direction = 4 //High = forward, Low = reverse ...Might be switched depending on shield
byte/#Define Speed = 3 //0-255 PWM
void setup()
{
pinMode(Enable, OUTPUT);
pinMode(Direction, OUTPUT);
pinMode(Speed, OUTPUT);
}
void loop()
{ /*your code here*/ }