First half : follow the path and on each side are point of interests, at each POI there are items that you need to reach the other riverside.

After that look out and find a big source of light in the forest.

Second half : look out there should be the home of the Skeleton Queen.

Bookshelf: all books are near the home of the Skeleton Queen except of one and this you will find if you watch some skeletons more closely ... they want to show you something.