Sunpak digiflash 3000 for Nikon?

I got this for christmas for my nikon d5100 dslr. I put the brand new batteries in, attached it to my camera… And nothing. Won't power up, anything. I even tried putting the batteries in opposite.Am i missing some important instruction?

Did you get the Sunpak version that works with Nikon?

Are you in auto mode on your D5100? If so, take it out of auto mode and see if you can get the flash to work.

But heavens sake, don't but your batteries in backwards! You will fry your flash unit.