The stitched piece
On the wrong side of the stitched piece, iron on interfacing material on it. This is to give body to the book. At the edges, I stitched it with white thread so not to let the the edge open up.
I used ribbon for tying . Therefore, stitched a matching ribbons beforehand at the edge as like the picture shows. The length of ribbons can be to your liking.
For the 'pages' of the book, I used felt. The amount of pages is up to your liking too. Here I used 3 pieces. One piece is to cover the whole wrong side,probably 1/4 inch smaller than the wrong side.. Then use slip stitch or blanket stitch method to stitch the edges of the felt to the edges of the book .For the remaining pages , simple backstitch at the middle will do to hold the entire pages together.