Spoiler
If you are at the beginning of the game, your first objective is figuring out how to communicate with the eel. Experiment with the book and the objects available to you to make changes to reality.
To talk to the eel you need to become younger. You can do this by reaching the kitchen (use the photo of the three lees in the kitchen on the picture on the 4th page of the book), get the drawing from the fridge, use the drawing on the author picture in the book).