Look up. 

NOTE these comments

TB6612FNG Arduino Sketch

Since this replaces the L298N, we can use the same sketch to drive the module. 

You can also use one of the many libraries available for the L298N, as any L298N code will work on this module.

The L298N Library by Andrea Lombardo is a well-documented library that you can install directly from your Arduino IDE.  It has several functions to make working with the L298N easier, and can also be used with the TB6612FNG.

/*
Author  : Andrea Lombardo
Site    : https://www.lombardoandrea.com
Source  : https://github.com/AndreaLombardo/L298N/

Here you can see how to work in a common configuration.

L298NX2 is not a new version of module or IC, 
but it stands for a double implementation of L298N library.

With L298NX2 is possible to initialize two motors at once.

Speed range go from 0 to 255, default is 100.
Use setSpeed(speed) to change speed for both motors,
setSpeedA(speed) or setSpeedB(speed) for individual changes.

Sometimes at lower speed motors seems not running.
It's normal, may depends by motor and power supply.

Wiring schema in file "L298NX2 - Schema_with_EN_pin.png"
*/

// Include the (new) library
#include <L298NX2.h>

// Pin definition
const unsigned int EN_A = 10;
const unsigned int IN1_A = 9;
const unsigned int IN2_A = 8;

const unsigned int IN1_B = 7;
const unsigned int IN2_B = 6;
const unsigned int EN_B = 5;

// Initialize both motors
L298NX2 motors(EN_A, IN1_A, IN2_A, EN_B, IN1_B, IN2_B);

// Wait for Serial Monitor to be opened
while (!Serial) {
  //do nothing
}

// Set initial speed for both motors
motors.setSpeed(80);
}

void loop() {
  // Tell both motors to go forward (may depend by your wiring)
  motors.forward();

  // Alternative method:
  // motors.run(L298N::FORWARD);

  //print the motor status in the serial monitor
  printSomeInfo();digitalWrite(IN1, HIGH);

  motors.stop();

  // Alternative method:
  // motors.run(L298N::STOP);

  printSomeInfo();

  delay(3000);

  // Change individual speeds
  motors.setSpeedA(255);
  motors.setSpeedB(90);

  // Tell motor A to go back (may depend by your wiring)
  motors.backwardA();

  // Alternative method:
  // motors.runA(L298N::BACKWARD);

  // Tell motor B to go forward (may depend by your wiring)
  motors.backwardB();

  // Alternative method:
  // motors.runB(L298N::FORWARD);

  printSomeInfo();

  delay(3000);

  // Stop
  motors.stop();

  printSomeInfo();

  // Change individual speeds
  motors.setSpeedA(90);
  motors.setSpeedB(255);

  delay(3000);
}

/*
Print some informations in Serial Monitor
*/
void printSomeInfo() {
  Serial.print("Motor A is moving = ");
  Serial.print(motors.isMovingA() ? "YES" : "NO");
  Serial.print(" at speed = ");
  Serial.println(motors.getSpeedA());
  Serial.print("Motor B is moving = ");
  Serial.print(motors.isMovingB() ? "YES" : "NO");
  Serial.print(" at speed = ");
  Serial.println(motors.getSpeedB());
}

Just start with the sample and slowly use archive and modify, if it breaks go back one archive and try again.

Good luck.

p.s. Archive is in the Tools menu, see pic.

  if (!AFMS.begin()) {         // create with the default frequency 1.6KHz
  // if (!AFMS.begin(1000)) {  // OR with a different frequency, say 1KHz
    Serial.println("Could not find Motor Shield. Check wiring.");
    while (1);
  }
  Serial.println("Motor Shield found.");

/*
This is a test sketch for the Adafruit assembled Motor Shield for Arduino v2
It won't work with v1.x motor shields! Only for the v2's with built in PWM
control

For use with the Adafruit Motor Shield v2
---->	http://www.adafruit.com/products/1438
*/

#include <Adafruit_MotorShield.h>

// Create the motor shield object with the default I2C address
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
// Or, create it with a different I2C address (say for stacking)
// Adafruit_MotorShield AFMS = Adafruit_MotorShield(0x61);

// Select which 'port' M1, M2, M3 or M4. In this case, M1
Adafruit_DCMotor *myMotor = AFMS.getMotor(1);
// You can also make another motor on port M2
//Adafruit_DCMotor *myOtherMotor = AFMS.getMotor(2);

void setup() {
  Serial.begin(9600);           // set up Serial library at 9600 bps
  Serial.println("Adafruit Motorshield v2 - DC Motor test!");

  if (!AFMS.begin()) {         // create with the default frequency 1.6KHz
  // if (!AFMS.begin(1000)) {  // OR with a different frequency, say 1KHz
    Serial.println("Could not find Motor Shield. Check wiring.");
    while (1);
  }
  Serial.println("Motor Shield found.");

  // Set the speed to start, from 0 (off) to 255 (max speed)
  myMotor->setSpeed(150);
  myMotor->run(FORWARD);
  // turn on motor
  myMotor->run(RELEASE);
}

void loop() {
  uint8_t i;

  Serial.print("tick");

  myMotor->run(FORWARD);
  for (i=0; i<255; i++) {
    myMotor->setSpeed(i);
    delay(10);
  }
  for (i=255; i!=0; i--) {
    myMotor->setSpeed(i);
    delay(10);
  }

  Serial.print("tock");

  myMotor->run(BACKWARD);
  for (i=0; i<255; i++) {
    myMotor->setSpeed(i);
    delay(10);
  }
  for (i=255; i!=0; i--) {
    myMotor->setSpeed(i);
    delay(10);
  }

  Serial.print("tech");
  myMotor->run(RELEASE);
  delay(1000);
}

#include <Wire.h>
#include <Adafruit_MotorShield.h>

// Create the motor shield object with the default I2C address
Adafruit_MotorShield AFMS = Adafruit_MotorShield();

// Connect motor(s) to M1 and M2
Adafruit_DCMotor *motor1 = AFMS.getMotor(1);
Adafruit_DCMotor *motor2 = AFMS.getMotor(2);

void setup() {
Serial.begin(9600); // set up Serial library at 9600 bps
Serial.println("Adafruit Motorshield v2 - Motor test!");

AFMS.begin(); // create with the default frequency 1.6KHz

Serial.println("Motor test!");

motor1->setSpeed(255);
motor2->setSpeed(255);
}

void loop() {
Serial.println("Forward");
motor1->run(FORWARD);
motor2->run(FORWARD);
delay(2000);

Serial.println("Backward");
motor1->run(BACKWARD);
motor2->run(BACKWARD);
delay(2000);

Serial.println("Release");
motor1->run(RELEASE);
motor2->run(RELEASE);
delay(1000);
}