Divider boards go in the back of the camera, they allow you to make two 8x5 or 4x10 exposures, or four 4x5 exposures on one sheet of 8x10 film. I have a set for my Deardorff V8. "DDS" in this case means "double dark slide" - what we call a "filmholder". You can modify the darkslide by cutting it in half, so it masks half the sheet, but you'll need an expendable darkslide.
Originally Posted by Doc W