You need 2 6 pins to connect to it. There connectors that came with it are molex connectors if you do not have 1/2 6 pin than you would put the 2 molex in for the 6 pin to go in the card. It's pretty straight forward you should have at least looked at a reference picture if you had no idea what to do with the card.
Also what power supply do you have..
My PSU has a cable with 2 six pin connectors. However, the 6850 power connectors have the center 12 v pin removed on both inputs. I was wondering if I used the 2 six pin connectors from my PSU with the center 12 v pin in, would I run the risk of shorting something?
I could find no schematic either on the manual or the 'net.