That's simple, one person give a gift to another person but, the one who receive the doesn't know who gave them the gift.
You only have to go to the index.php. There, you can add as many entry as you want and of course completed them.
When you got everything done, you can click on the button "Generated" or "Générer" then, you got what you want.
You can write it down, but I don't like that and neither do you.
You can download the text file where everything is written at the end of the list.