Pause Screen

//in game manager
// pause screen is a UI panel
//pause menu
    public GameObject pauseScreen;
    private bool paused;

     void ChangePaused()
    {
        if (!paused)
        {
            paused = true;
            pauseScreen.SetActive(true);
            //game slows down to zero speed
            Time.timeScale = 0;
            //lets music play (doesn't require ref to audio source)
            AudioListener.pause = true;
        }
        else
        {
            paused = false;
            pauseScreen.SetActive(false);
             //game plays at normal speed
            Time.timeScale = 1;
            //stops music playing (doesn't require ref to audio source)
            AudioListener.pause = false;
        }
    }

     void Update()
    {
        if (Input.GetKeyDown(KeyCode.P))
        {
            ChangePaused();
        }
    }