I had so many leftover floppy disk for which I don't even have a disk drive anymore. This idea turned out to be really useful, that's why I share it with you.
Now you can attach the bottom. Turn your box around and lay the fifth disk on top. Now take the sharpie and mark two points close to the edge where you’ll punch the holes. Some disks have small indentions (as can be seen in the next picture) which you can take as an orientation. On the disks which you’ll affix the bottom disk to, mark two points like shown in the picture.