Step 5: turn the book right side out
Place your fingers in the opening between the two fabrics and turn it right side out. Don't try to turn it between the felt and fabric, or you'll end up with the wrong things on the outside.
Be gentle while turning! You can rip stitches if you get hasty with it. Once it's turned right side out, use a pen or a crochet hook to push the corners out so they look nice. :)