You will need to print both files on the same sheet, back to back.. It may take a try or two until you get them matched correctly. Light card stock (67 lb.) works best. They look nice on any light color. For best results use a 600 dpi laser printer. Once printed correctly, cut off the margins and then cut the sheet into fours. You should have four Preflighter cards ready to be folded in the middle. If you want an extra nice touch, have a light "flash" lamination applied. They will still be foldable and will last forever.