7.
Use the scalpel to cut off the excess of the paste off.
As you can see I filled holes in the styrofoam with some paste. If you don't fill them they might be visible from underneath the paste - go to step 15 to see what happens if the styrofoam is not smoothed properly or if the holes are not filled.
Before proceeding to the next step I pinched the corners of the text block to make the pages look more square (in the photo above they are still round).