Can someone please help me understand the noise tokens

I understand the general idea of what the tokens are for. The confusion for me lies in which tokens take priority. Say in the same turn I generate 3 tokens on the top of the board and 1 token at the bottom of the board. When it's the zombies turn do they all go to the top where the most overall noise is or will they go to the bottom where the most recent noise was made? How does that work?