Unity c# Car Movement script

I'm in the process of writing a script for a car that has normal movement. But I'm having trouble steering the tires should be able to rotate forward and the other tire backward when you steer depending on the direction of one tire. The model must be able to turn on the spot. I don't know how to write the application can someone help?

    using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Wheel : MonoBehaviour
{
    public WheelCollider wheelColliderLeftFront;
    public WheelCollider wheelColliderRightFront;
    public WheelCollider wheelColliderLeftBack;
    public WheelCollider wheelColliderRightBack;

    public Transform wheelLeftFront;
    public Transform wheelRightFront;
    public Transform wheelLeftBack;
    public Transform wheelRightBack;


    public float motorTorque = 100f;
    public float maxSteer = 20f;
    Rigidbody carRigidbody;


    void Start()
    {
        carRigidbody = GetComponent<Rigidbody>();
    }
    void FixedUpdate()
    {
        wheelColliderLeftBack.motorTorque = Input.GetAxis("Vertical") * motorTorque;
        wheelColliderRightBack.motorTorque = Input.GetAxis("Vertical") * motorTorque;
        wheelColliderLeftFront.steerAngle = Input.GetAxis("Horizontal") * maxSteer;
        wheelColliderRightFront.steerAngle = Input.GetAxis("Horizontal") * maxSteer;

    }

    private void Update()
    {
        var pos = Vector3.zero;
        var rot = Quaternion.identity;
        wheelColliderLeftFront.GetWorldPose(out pos, out rot);
        wheelLeftFront.position = pos;
        wheelLeftFront.rotation = rot;

        wheelColliderRightFront.GetWorldPose(out pos, out rot);
        wheelRightFront.position = pos;
        wheelRightFront.rotation = rot;

        wheelColliderLeftBack.GetWorldPose(out pos, out rot);
        wheelLeftBack.position = pos;
        wheelLeftBack.rotation = rot;

        wheelColliderRightBack.GetWorldPose(out pos, out rot);
        wheelRightBack.position = pos;
        wheelRightBack.rotation = rot;
    }

}