Take a thin cardboard( can be a cereal box) and cut in the size that you want. I cut a 5.5" x 8" piece for mine, but you can make it as small or large as you wish.
Sew up the button in the front of the notebook and leave some extra seam thread (enough to make a turn around the notebook)
Grab your paper for the inside pages and trim them down so they are slightly smaller than the notebook (about 1/4" shorter on all sides).
With the needle and embroidery floss, stitch the paper to the notebook down the spine.
Tie a knot or sew, you choose.
Apply glue or tape to your decorative paper and attach it to the spine of the notebook. PS:For a more finished look, cut rounded corners on all four edges of the notebook. :) Hope you like it!