The Mia videotape is acquired in the main house. Once you enter the main hall, go upstairs and enter the door on the west. Turn left, go past the shelf with the American football helmet on it, move past the door with the dead snake, and enter the brown door you'll see on the right at the end of the corridor. This is the recreation room. Mia's tape will be next to the TV and VHS player. You can play the tape right here.

Avoiding Marguerite is a matter of patience. You'll have to stealthily make your way through the old house whenever she's near you.

When you enter the old house, go left, then right and enter the door. Turn right and make your way through this room to the door on the other side. Go through this door and you'll notice a large crate in front of you. Get ready to hide behind this crate. Turn the corner to trigger Marguerite, then step back a little and crouch behind the crate. Wait for Marguerite to go through the door on the right, then leave and head past the door Marguerite came from.

Ignore the shadow plinth puzzle for now, exit the double doors, then turn right and hide in this corner. Wait for Marguerite to go away, then interact with the shadow plinth and solve the puzzle to uncover a secret passage behind the wall. Get into this passage and move to the next area.

In front of you is a small "island" that consists of boxes, wood, and a table. You'll have to crouch behind here and wait for Marguerite to walk past before continuing. Once Marguerite has moved on, continue forward and to the right. Hop down into the floor where the wood is broken. Make your way to the end of this passage, then the lights will turn out and a cutscene will play.

As long as you weren't spotted, the achievement will unlock upon exiting the tap