It’s time to collect the eight Red Coins in the level, all of which are in the main mansion, so enter through the main doors. On the first floor, enter the first door on the left, where you will see a piano in the corner. Get close enough for it to start moving, then go behind it to find Red Coin #1. Enter the other door in this room to find yourself in the one room with the possessed chairs. Jump to the top of the bookshelves in this room to find Red Coin #2 and Red Coin #3. Back in the main lobby, enter the first room on the right side from the entrance.
This will be the one with the thin ledges, as well as a Boo for Go On a Ghost Hunt; Red Coin #4 will be right there in the middle of the room. Return to the lobby once more, then go through the door immediately to your left at the top of the stairs. You will be in a room with some wire-frame grate floor, and Red Coin #5 will be along the wall opposite the entrance. Go into the main lobby and enter the first door immediately to your right from the top of the stairs. There will be some coffins in the back room here, some of which will pop up.
Red Coin #6 and Red Coin #7 will be under two of those coffins, the first one on the right and the middle one on the left side. For the last coin, enter the door to the right of the previous one in the main lobby. Go to the other side of the bookshelf to find Red Coin #8 sitting in the open; watch out for the floor near it, as it will move and you can fall all the way to the merry-go-round area. Once you’ve collected the last coin, the star will spawn in the main lobby, on the second floor.