Triggers? How do I use them to stop the timer?

Unity Engine
1

When the player passes though the “WinZone” (Has a box collider with isTrigger checked) I want to stop the timer on the Timer.cs . I don’t know how to use triggers though, and any advice would help!

My Code for Timer

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Internal;
using TMPro;

public class Timer : MonoBehaviour
{

    public TextMeshProUGUI timerText;
    public TextMeshProUGUI highscore;
    private float startTime;
    private bool finished = false;

    void GameFinished()
    {
        float t = Time.time - startTime;
        if (t < PlayerPrefs.GetFloat("HighScore", float.MaxValue))
        {
            PlayerPrefs.SetFloat("HighScore", t);
            highscore.text = t.ToString();
            PlayerPrefs.Save();
        }
    }

    void Start()
    {

        startTime = Time.time;
        highscore.text = PlayerPrefs.GetFloat("HighScore", 0).ToString();
    }


    void Update()
    {

        float t = Time.time - startTime;
        string minutes = ((int)t / 60).ToString();
        string seconds = (t % 60).ToString("f2");
        timerText.text = minutes + ":" + seconds;
        if (/* Check if player finished the game */)
            GameFinished();

    }
}

My Code for WinZone

// This script is responsible for detecting collision with the player and letting the
// Game Manager know
using UnityEngine;

public class WinZone : MonoBehaviour
{
    int playerLayer;    //The layer the player game object is on


    void Start()
    {
        //Get the integer representation of the "Player" layer
        playerLayer = LayerMask.NameToLayer("Player");
    }

    public void OnTriggerEnter2D(Collider2D win)
    {
        //If the collision wasn't with the player, exit
        if (win.gameObject.layer != playerLayer)
            return;

        //Write "Player Won" to the console and tell the Game Manager that the player
        //won
        Debug.Log("Player Won!");
        GameMaster.PlayerWon();
    }
}
2

Create a bool in Timer.cs ‘hasWon’.

Check if the Player has won in Update:

void Update()
    {

        if(!hasWon){
            float t = Time.time - startTime;
            string minutes = ((int)t / 60).ToString();
            string seconds = (t % 60).ToString("f2");
            timerText.text = minutes + ":" + seconds;
        }
    }

Then in WinZone, change hasWon to true when the Player collides (find Timer.cs first):

public void OnTriggerEnter2D(Collider2D win)
    {

        if (win.gameObject.layer == playerLayer){
            Debug.Log("Player Won!");
            GameMaster.PlayerWon();
            Timer.hasWon = true;
        }
    }