Again, review the manual settings and diagram to determine where each plug will fit. Another caution note is to look carefully at the case at the time of purchase to make sure that the wiring plugs are marked. Most are, but take no chances. In these cases, the wiring plugs were identified. Next, find the Multifunction connector on the motherboard and in the diagram and other document printouts.
Most manuals indicate which pin is the positive voltage pin and mark or indicate it.
In the Viking 3 case, the positive pin is noted as black for the positive. The case wiring plugs usually have black and another color wiring. The black wire side is the positive. There are case plugs for Speaker, power LED, Turbo LED, HDD LED, and Reset button in the systems we assembled. The Multifunction connector diagram was well marked, making the actual plug-in easy.