As soon as you enter the second floor turn right and flip the light switches.
Look to the left side and you'll see a bookshelf. Open the lower cabinet and examine the cassette tape, then drop it and you'll receive another journal entry.
Keep walking towards the end of the hallway and examine the letter posted on the board. Then enter the room on the right side of it.
As you enter the room you'll notice a locker near the bed. Leave it for now but remember this place. Now exit through the other door inside the room and look to the right. There's a backpack there with a note underneath.
Now go to the door at the end of the corridor near the window. Turn on the lights and approach the tub. You'll find some red liquid. Look at the left side of the tub and you'll find a red bottle. Examine it and you'll receive another journal entry.
Now leave the toilet and go to the door directly in front of the corridor. Turn the lights on and head for the night table at the right side of the bed. There's a note inside the drawer and also there's a book and a bookmark under the bed. There's a note written on the book mark.
Leave your parents's room and turn left. Enter the door at the end of the corridor and read the note that's under the door.
Tun on the light inside the room and head for the bed. Turn on the lamp and examine the note beside it. Now look to your right and you'll see a black notebook. Examine that one too and then leave the room.
After leaving the guest room turn right and enter the door that's open on the right wall. There are a couple of shelves behind the easel. Open the drawer on one of the shelves and you'll find another note. Examine it to receive another journal entry.
Enter the other door in the room near the shelves. Behind the door there's a table with a book and folder on top of it. Open the folder and examine the map. You'll receive a hidden location on your map.
Now go back to your parents's room and enter the closet. Turn on the light and examine the wall at the very back.
The wall will then open a secret passage that leads downstairs. Climb down the stairs and turn on the light.
You'll find another map at the wall in front of the stairs. Examine it and you'll receive some more locations that you can explore.