I sent them two copies of a physical deck, but I think they'll accept a CD format as well. But if it's easier to print out a set of cards, then do that. They just need something they can 'see'. There should be a number to call for assistance, on the site, if you need to ask them something.
The form you use is the VA (Visual Aids) short form, unless the deck is a derivitive of some other work, then you use the long form. They actually DO keep everything filed away somewhere. Makes you wonder how many warehouses are filled with stuff just from things sent to them.
The check goes with the package you send, and don't expect to see return paperwork with your assigned number for about 9 months. There used to be a turnaround of only 3 months, but after 9/11 everything slowed down considerably. However, soon as your package hits the mail going out to them, you're covered 'officially' by copyright.