How do I switch from * Input.GetAxis () * to UI buttons?

Hello! How do I switch from Input.GetAxis () to UI buttons in my code? The code below rotates an object on the Z axis depending on how long you hold down the arrows on the keyboard. It works perfectly on the keyboard but I want to put it on UI buttons. I tried a few ways but they didn't work . Can you help me please?

 public float Rotation_Speed;
     public float Rotation_Friction; 
     public float Rotation_Smoothness; 
 
     private float Resulting_Value_from_Input;
     private Quaternion Quaternion_Rotate_From;
     private Quaternion Quaternion_Rotate_To;
 
     public void RotateUp()
     {
         Resulting_Value_from_Input += Input.GetAxis("Horizontal") * Rotation_Speed * Rotation_Friction; 
         Quaternion_Rotate_From = transform.rotation;
         Quaternion_Rotate_To = Quaternion.Euler(0, 0, Resulting_Value_from_Input);
 
         transform.rotation = Quaternion.Lerp(Quaternion_Rotate_From, Quaternion_Rotate_To, Time.deltaTime * Rotation_Smoothness);
     }
     public void RotateDown()
     {
         Resulting_Value_from_Input += Input.GetAxis("Horizontal") * Rotation_Speed * Rotation_Friction; 
         Quaternion_Rotate_From = transform.rotation;
         Quaternion_Rotate_To = Quaternion.Euler(0, 0, Resulting_Value_from_Input);
 
         transform.rotation = Quaternion.Lerp(Quaternion_Rotate_From, Quaternion_Rotate_To, Time.deltaTime * Rotation_Smoothness);
     }