Where to plug in the plug on the video card

I purchased a new video card and it was installed fine, but it had some wires that needed to be plugged in somewhere. The Macintosh repair person could not find a proper place to plug it in. The old one did not have wires to plug in. This new one wouldn't work unless it was plugged into something, so he plugged into the unit above, which allowed the computer to work for a short time and then it froze. What can we do now?

Thank you very much for your suggestion. I plugged the molex connector into what was suggested on the PDF. The computer worked for a little while and then froze again. What is a molex splitter? Is it the same as the molex connector? Could there be an incompatibility issue or might there be some software I need to download?