how to comunicate arduino and wifi shield dfrobot v2.2

greeting from malaysia

im now doing my last year semester on how to control RC Car using laptop..
the serial connection cable can move the rc car..

below are the code on my arduino and hopefully somebody could teach me@correct (A.S.A.P) any error in my code on how to connects wife-shield with dfrobot v2.2

-Code-

// (PWM arduino digital output) 
int motorPin1  = 5; 
int motorPin2  = 6; 
int motorPin3  = 10; 
int motorPin4  = 11; 

// Only if you want lights on your car
int lights = 9; 

int state;
int vSpeed=100;     // Default speed
int i=0;

void setup() {
    // Set pins as outputs:
    pinMode(motorPin1, OUTPUT);
    pinMode(motorPin2, OUTPUT);
    pinMode(motorPin3, OUTPUT);
    pinMode(motorPin4, OUTPUT);
    pinMode(lights, OUTPUT);
    // Open serial communications and wait for port to open:
    Serial.begin(115200);
}
 
void loop() {
  
  if (Serial.available()>0){
    
    state = Serial.read();   
    
    
    
    /***********************Forward****************************/
    // If the "state" is 'F', car will go forward
    if (state == 'f') {
       digitalWrite(motorPin1, vSpeed);
         digitalWrite(motorPin2, LOW); 
        digitalWrite(motorPin3, LOW); 
        digitalWrite(motorPin4, LOW); 
        Serial.println("ArduiCar: Forward");
    }

    /***********************Backward****************************/
    // If the "state" is 'B', car will go backward
    else if (state == 'b') {
       digitalWrite(motorPin2, vSpeed);
         digitalWrite(motorPin1, LOW); 
        digitalWrite(motorPin3, LOW); 
        digitalWrite(motorPin4, LOW);
        Serial.println("ArduiCar: Backward");
    }
    /***************************Left*****************************/
    // If the "state" is 'L', car will turn left
    else if (state == 'l') {
        digitalWrite(motorPin3, 0);
        digitalWrite(motorPin4, 128);
        Serial.println("ArduiCar: Left"); 
    }
    /***************************Right*****************************/
    // If the "state" is 'R', car will turn right
    else if (state == 'r') {
        digitalWrite(motorPin4, 0); 
        digitalWrite(motorPin3, 128);   
        Serial.println("ArduiCar: Right");
    }
    /************************Lights*****************************/
    // If the "state" is 'l' turn lights on
    else if (state == 's') {
        if (i==0){
          digitalWrite(lights, HIGH); 
          Serial.println("ArduiCar: Lights on");
          i=1;
        }
        else if (i==1) {
          digitalWrite(lights, LOW); 
          Serial.println("ArduiCar: Lights off");
          i=0;
        }
    }
    // If the "state" is 'o' all stop and set speed low
    else if (state == 'o'){
        digitalWrite(motorPin1, LOW); 
        digitalWrite(motorPin2, LOW); 
        digitalWrite(motorPin3, LOW);
        digitalWrite(motorPin4 , LOW);
        Serial.println("ArduiCar: Stop");
    }
  }
}

thank you

correct (A.S.A.P) any error in my code on how to connects wife-shield with dfrobot v2.2

If you can't figure out to connect a shield to an Arduino, do you really feel ready to graduate?

The code you posted does something. You didn't bother saying what.
You want the code to do something. "Control the robot" is so vague as to be useless.