Here is my 100% achievement guide and full walkthrough for Tell Me Why.
This is story related and cannot be missed.
When you get outside the Ronan house hold, try the front door. LOCKED.
Go around to the right side of the house where you find some wooden boards seemingly boarding up a hole.
Interact with it to find out you can't get through either.
To the right of the house is a barn with a locked door, again, around to the right go to the window and see the screwdriver inside.
From here, go back to the left side of the barn (right side away from the house) and you see 3 frogs, interact with the middle one to grab the key.
Go back tk the locked door, grab the screwdriver and go back tk the boarded up hole (right side of house).
Navigate this easy underneath the house part and when you enter from beneath, the achievement unlocks!
Go to 39:20 in my video to see where and what to do to unlock this
Hope this helps!