public void onPreviousButtonClick()
    {
        index -= 1;

        if (!instructTextBox.IsActive())
        {
            instructTextBox.gameObject.SetActive(true);
        }

        if (index > -2)
        {
            if (index == -1)
            {
                logoImage.SetActive(true);
                tutorialImage.SetActive(false);
                goalText.SetActive(false);
                cheeseImage.SetActive(false);
                instructTextBox.text = instructList[index + 1];
            }
            else if (index > -1)
            {
                logoImage.SetActive(false);
                tutorialImage.SetActive(true);
                goalText.SetActive(false);
                cheeseImage.SetActive(false);
                tutorialVideoPlayer.clip = tutorialClips[index];
                instructTextBox.text     = instructList[index + 1];
            }
        }
        else
        {
            index = -1;
        }
    }