How do I control my car with UI buttons?

I have a car controller witch works with a keyboard, but I want to make my game playable on mobile and I can not get the buttons to work and I am stuck.

here are the scripts that are controlling the car

 public Transform centerOfMass;
 public float motorTorque = 1500f;
 public float maxSteer = 20f;

 public float Steer { get; set; }
 public float Throttle { get; set; }

 private Rigidbody rb;
 private Wheel[] wheels;

 

 public float ThrottleInput { get; private set; }
 public float SteerInput { get; private set; }

 void Start()
 {
     wheels = GetComponentsInChildren<Wheel>();
     rb = GetComponent<Rigidbody>();
     rb.centerOfMass = centerOfMass.localPosition;
 }

 void Update()
 { 
     Throttle = Input.GetAxis("Vertical");
     Steer = Input.GetAxis("Horizontal");
     
     foreach (var wheel in wheels)
     {
         wheel.steerAngle = Steer * maxSteer;
         wheel.Torque = Throttle * motorTorque;
     }
 }

This one is on the cars parent

 public bool Steer;
 public bool invertSteer;
 public bool power;

 public float steerAngle { get; set; }
 public float Torque { get; set; }

 private WheelCollider wheelCollider;
 private Transform WheelTransform;


 void Start()
 {
     wheelCollider = GetComponentInChildren<WheelCollider>();
     WheelTransform = GetComponentInChildren<MeshRenderer>().GetComponent<Transform>();
 }

 
 void Update()
 {
     wheelCollider.GetWorldPose(out Vector3 pos, out Quaternion rot);
     WheelTransform.position = pos;
     WheelTransform.rotation = rot;
 }

 private void FixedUpdate()
 {
     if (Steer)
     {
         wheelCollider.steerAngle = steerAngle * (invertSteer ? -1 : 1);
     }
     if (power)
     {
         wheelCollider.motorTorque = Torque;
     }
 }

And this one is on the wheels

I have also tried to switch to the new input system but that made more problems so if it is possible I would like to also keep it in the old input system.