Here is my 100% Achievement guide and full walkthrough for Tell Me Why (Chapter 2).
We will end up in the store where Alyson says she will work behind the till, and we, as Tyler, have to go into the back room and help out big Mike. These are where the 3 posters we need to click are located.
You will have a small bit of conversation and he asks you to count tomato sauce and bleach.
When the convo ends we can start this achievement.
Poster 1 - Directly behind where Mike is standing (Reference to Dontnods Life Is Strange).
Poster 2 - From Poster 1, head left (Not through the double doors of course, but down the aisle of the back room) and you will see another poster which has "The Red Queen" wine bottle on it. (Refernece to Vampyrs last boss the red queen).
Poster 3 - From poster 2, head right and go towards the other end of the back room to find A panda drinking an energy drink (my type of poster haha, also referencing Dontnods first game, Remember Me)
Once you click on all 3, Achievement unlocks.
Go to 1:20:25 to see where to get this
Hope this helps!