Here is how I completed the journal covers and put the whole thing together.
Fedex large box cut to 10 wide by 12-1/2 high. Slots cut to match the button holes on journal pages. (I thought it prudent to line the slots with masking tape to make the holes stronger.)
Washi tape adhered to the left edge of the front and back cover. Decorative scrapbook papers were adhered to the cardboard. (Not pictured here.) I used a mixture of 50% PVA glue and 50% methyl cellolose. This is a very strong glue used by book makers. One must work fairly quickly as it sets up fast. After both covers were covered with the scrapbook papers, they were set to dry overnight - with books on top to keep them lying flat when dry.
Four strips of twill tape (5/8" wide) cut - long enough to easily thread through button holes. (A few drops of FrayCheck on each end.) I used a safety pin as a needle.
Thread twill tape through button holes.
I found it easiest to pile up the complete journal and thread all the holes at one time.
I had to fiddle with the twill tape a bit to get everything even. Before knotting and cutting, I opened the journal to make sure the pages could easily be turned - tied square knot - trimmed twill tape and added more FrayCheck
My journal includes all of the project pages I made this year. I solved the problem of the smaller pages by inserting them into a clear plastic page protector.
Even the huge piece found its way into the journal. It folds up nicely and sits on the last page. I was so pleased that worked out since it's one of my favorites!