Cannot figure out how to find/edit specific levels when game not running

I am trying to learn Unity with books/Lynda and am learning while attempting to reskin a game from the Asset store. I click the play button in Unity to play/test the game, and when I do this I notice some settings I would like to change. One of them is the text that displays before a level. This text is different depending on the level objective. In the example I have provided, it says "Clear the top." I would like to change this and see exactly where it is that I can do this, but when I change it, Unity will not allow my changes to take place because the game is technically running, even though I've pressed the pause button. When I click the right arrow and fully stop the game, I cannot find the same file path that contains the text description for that particular level. It only has the text description for level one, and that's it. I have searched through every single folder and gone through everything I can think of to find out how to do this, and unfortunately I am at my last resort which is bothering this forum. Thank you so much for any help. I really appreciate it.