CDP200R - Can't figure out USB & SD Card...

I just purchased a CDP200 last week, and I'm trying to import a new piano sound and a different church organ sound, but I just can't figure out how. I've downloaded the data manager from Casio and gone to the music.casio/com site. From there, I downloaded a few samples of piano (salon piano) but I can't transfer them to my CDP (it keeps downloading as a CFK file - what in the world is that?).
It doesn't say anything in the manual about where to download new samples or how. It simply describes what to do with the data. WHAT DATA??

Where do I get good samples to transfer to the CDP
PLEASE HELP!!