The files are designed to be printed on two sides of one sheet of paper and then sliced in half with a paper cutter. If you do not have a duplex printer (a printer that can print on both sides at once), then print the first page, flip the stack over, load it back into your printer's paper tray and then print the second page. You may need to experiment with a page or two to make sure you're re-feeding the paper in the right direction.
After printing, cut on the dotted line. Then fold and nest the two pieces of paper into a booklet and put a staple in the middle of the fold. Voila! You have a neat and tidy Santarchy Carol book.