Read the book. Read the poem many times. Read book again slowly looking for clues.
If you want to find the treasure chest. Read the book just normally - the poem and the rest of the book. Then go back and read the poem 6, 8, 10 times. Study every line, ever word. Then after you do that read the book again slowly with the idea of looking for clues or hints that are in the book that will help you follow the clues (in the poem). You can find the chest with just the clues (in the poem), but there are hints in the book (Thrill of the Chase) that will help you with the clues (in the poem).