Script Problem

This script consult the transform.position of the object, the problem is that when i attach this script to diferent objects on the scene, doesnt work properly. My question is ¿How to make the script independent for diferents objects, so that it consult the transform.position of each one?

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Platform : MonoBehaviour
 {
     public float correctHight;
     public float playerCorrectSize;
     public bool transition;
     Controller player;
     Collider platformCollider;
 
     void Start()
     {
         correctHight = transform.position.y + (transform.localScale.y / 2);
         player = GameObject.FindObjectOfType<Controller>();
         platformCollider = GetComponent<Collider>();
     }
 
     void Update()
     {
         playerCorrectSize = (player.transform.position.y - (player.transform.localScale.y / 2));
         if (playerCorrectSize > correctHight && !transition)
         {
             platformCollider.isTrigger = false;        
         }
         else if(playerCorrectSize < correctHight - transform.localScale.y && !transition)
         {
             platformCollider.isTrigger = true;
         }
 
         if(Input.GetKeyDown(KeyCode.S) && player.onFloor && !platformCollider.isTrigger)
         {
             transition = true;
             platformCollider.isTrigger = true;
             StartCoroutine("waitTime");
         }
 
         if (transition) player.canJump = false;
     }
 
     IEnumerator waitTime()
     {
         yield return new WaitForSeconds(0.5f);
         transition = false;
         player.canJump = true;
     }
 }