How can I stick buttons on my cube and the same time using script?

Please help me I've been trying to figure out this for a month now...Yeah embarrassing... Well I have a cube with a script for rotating it and my problem is that I wan't to put buttons or idk something similar like "Piano Tiles" on the cube and still use my script for rotating it and also the buttons to be pressed. Please help me solve this issue I am new to game developing and C#.

Also if the code is bad I tried to make a code for touch dragging and rotating my cube feel free to make a brand new code.

Heres my code:

  private float rotationSpeed = 8.0F;
  private float lerpSpeed = 1.0F;
  private Vector3 theSpeed;
  private Vector3 avgSpeed;
  private bool isDragging = false;
  private Vector3 targetSpeedX;
  void OnMouseDown() {
      isDragging = true;
  }
  void Update() {
      if (Input.GetMouseButton(0) && isDragging) {
          theSpeed = new Vector3(-Input.GetAxis("Mouse X"), Input.GetAxis("Mouse Y"), 0.0F);
          avgSpeed = Vector3.Lerp(avgSpeed, theSpeed, Time.deltaTime * 0);
      } else {
          if (isDragging) {
              theSpeed = avgSpeed;
              isDragging = false;
          }
          float i = Time.deltaTime * lerpSpeed;
          theSpeed = Vector3.Lerp(theSpeed, Vector3.zero, i);
      }
      transform.Rotate(Camera.main.transform.up * theSpeed.x * rotationSpeed, Space.World);
      transform.Rotate(Camera.main.transform.right * theSpeed.y * rotationSpeed, Space.World);