These designs are formatted for Avery Embossed Note Cards, stock number 3268 (available at office supply stores and in the 'paper' section of many general-merchandise stores.)  You can also print the card design on any good-quality paper that will work in your printer.

To print both the cover and the inside of a card, start by printing the cover.  After printing, remove the page of cards from the printer, turn it over and return it to the paper tray (upside down -- read your printer instructions or experiment on blank paper!) to print your message on the inside.