Rotate Camera using a joystick or buttons

Hello Everyone, I've been struggling with this problem, I have a working FPS Camera script attached to a camera and capsule I want to transfer it to a joystick or buttons this is my script :

         using UnityEngine;
         using System.Collections;
         
         [AddComponentMenu("Camera-Control/Mouse Look")]
         public class MouseLook : MonoBehaviour
         {
         
             public enum RotationAxes { MouseXAndY = 0, MouseX = 1, MouseY = 2 }
             public RotationAxes axes = RotationAxes.MouseXAndY;
             public float sensitivityX = 15F;
             public float sensitivityY = 15F;
         
             public float minimumX = -360F;
             public float maximumX = 360F;
         
             public float minimumY = -60F;
             public float maximumY = 60F;
         
             float rotationY = 0F;
         
             void update()
             {
                 if (axes == RotationAxes.MouseXAndY)
                 {
                     float rotationX = transform.localEulerAngles.y + Input.GetAxis("Mouse X") * sensitivityX;
         
                     rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
                     rotationY = Mathf.Clamp(rotationY, minimumY, maximumY);
         
                     transform.localEulerAngles = new Vector3(-rotationY, rotationX, 0);
                 }
                 else if (axes == RotationAxes.MouseX)
                 {
                     transform.Rotate(0, Input.GetAxis("Mouse X") * sensitivityX, 0);
                 }
                 else
                 {
                     rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
                     rotationY = Mathf.Clamp(rotationY, minimumY, maximumY);
         
                     transform.localEulerAngles = new Vector3(-rotationY, transform.localEulerAngles.y, 0);
                 }
             }
         }
     
 I already have Left Right Up Down buttons in a Canvas how can I transfer the script so I can rotate it with buttons

thank you so much