Help car drive forward using rigidbidy

Help! I'm trying to get my car to drive forward (in the direction i'm facing) when pressing w. Unfortunately so far I've only been able to add an upwards force to the car so far using the below code. Sorry it's messy. Any advice would be great.

This is the main movement code: car.GetComponent().AddForce(forward, ForceMode.Acceleration);

(forward is something detailed below)

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

public class Drive : MonoBehaviour { public GameObject car; Vector3 rotation;

 //Vector3 velow;
 float velox;
 float veloy;
 float veloz;

 // Start is called before the first frame update
 void Start()
 {

 }

 private void Update()
 {
     //velow = this.gameObject.GetComponent<Rigidbody>().velocity.w;
     velox = car.gameObject.GetComponent<Rigidbody>().velocity.x;
     veloy = car.gameObject.GetComponent<Rigidbody>().velocity.y;
     veloz = car.gameObject.GetComponent<Rigidbody>().velocity.z;
 }





 
 void FixedUpdate()
 {
     Vector3 myvelocity = new Vector3(velox, veloy, veloz);
     rotation = this.gameObject.transform.eulerAngles;
     Vector3 forward = Vector3.RotateTowards(rotation, Vector3.left,0f, 1f);
     //Vector3 direction = rotation * Vector3.forward;

     if (Input.GetKey(KeyCode.W))
     {
         //this.gameObject.transform.Translate(Vector3.forward * Time.deltaTime * 10);
        
         car.GetComponent<Rigidbody>().AddForce(forward, ForceMode.Acceleration);
         //car.GetComponent<Rigidbody>().AddForce(rotation * ForceMode.Acceleration);
         //car.GetComponent<Rigidbody>().AddForce(direction, ForceMode.Impulse);

     }