Sims 3 Mod (Master Controller)

        Today I downloaded the Master Controller after looking at heaps of videos showing you how. I found a really good video with heaps of good comments. So I download everything how it said. Then it came to the point where I open my game to the second main screen (the one where you pick a saved game). It said a blue box should pop up saying that the game has found a Mod. Well I did all that but no boxed popped up saying that it had found a mod. I really confused and annoyed. Please, please, please help. 

By the way, I'm a Mac user (and new to it as I got my computer for Christmas(2013) but I'm not new to Sims 3 saying I've been playing it since it was released, but I have just got in to Mods).

Thanks so much.