Enemies on Lerpz 3d tutorial are not moving forward

Hi everyone! I'm doing the Lerpz 3d tutorial and I'm not able to make the enemies move towards me, they're rotating but not moving. I had a look on the "EnemyPoliceGuy.js" and found the code that should make move the enemies.

 // Just move forward at constant speed
    direction = transform.TransformDirection(Vector3.forward * attackSpeed);
    characterController.SimpleMove(direction);

I've looked in other places to find what else is people doing but its always more or less the same.

I'd really apreciate some advice on how to solve this issue if someone have made this tutorial.

Best regards!