Thick material (outdoor fabric works well)
This was the original that I used for this quiet book.
To get the pattern I laid the new pages on top of fabric and made a shape similar to this.
I cut two. Stitched the two right-sides together, leaving an opening. Turned it right-side out and top-stitched the entire cover.
To help get the corners square, cut angles out of the seam allowance before turning right side out.
Sew all the pages together. Pin in place.
Leave an opening at the top so you can turn it right side out. Press the edges and top-stitch each set of pages.
Sew all the pages into the quiet book. This is kind of a wrestling match, but well worth it. Remove all the "extra" pieces from the pages while sewing the pages in place.
I added a strap to the outside of the cover once the pages were sewn in place.
Add a button hole to the angled side of the cover.
I hadn't added the snaps yet, they go on the top and bottom edges of the cover.