How to instantiate and destroy objects with 2d trigger

I am making a 2d game: Car Escape.

I want to make 50 levels in one scene. Levels are prefabs and I need some help with code. How can I make level 1 show initially and if I passed level 1, instantiate level 2 and destroy level 1 with OnTriggerEnter2D, etc.

 public class WinZoneScript : MonoBehaviour {
     
         // Reference to WinText game object
         public GameObject []levels;     //levels map
         public GameObject panel;    //panel  next button to go to next level
         public int level;    // number of ever levels 
     
         //Use this for initialization
         void Start ()
         {
             panel.gameObject.SetActive(false);
             level = PlayerPrefs.GetInt("level", level);
             levels[level].gameObject.SetActive(enabled);
         }
     
         // If target car (red one) exits the playground
         void OnTriggerEnter2D (Collider2D col)
         {
             // then "You Win!" sign is turned on
             
             levels[level].gameObject.SetActive(false);
             panel.gameObject.SetActive(enabled);
             PlayerPrefs.SetInt("level", level);
         }
     
         public void Next()
         {
             PlayerPrefs.GetInt("level", level);
             panel.gameObject.SetActive(false);
             PlayerPrefs.Save();
         }