Hi! Here are some tips:
1. The monster hears you running far away, so it's better to walk than run.
2. The monster DOES NOT SEE through walls. He can see from a distance, but cannot see through walls.
3. When you collect the page, the monster runs to the place where the page was. First, make sure the monster is somewhere far away from you. Then collect the page and run a bit to the side and stand still. The monster will run to the place where the page was and will go its own way.
I saw videos on youtube where people used these tips and won. When I tested the game, I also failed at the beginning, but later I managed to win.