The black color of the wire designates it as a ground wire and if your cables are not labeled as +/- the black wire would go on the (-) side of the connection, the (-) being the ground on the board and the black wire the cable ground. This is a pain without the proper documentation unless the board is marked clearly such as the case with the board we were using in this article. As you can see in the photo below even without the manual this board is labeled clearly enough to understand and implement.
If you have just purchased a new motherboard read your manual cover to cover and familiarize the layout of the board and where the proper connections go. This will make your task much simpler than just feeling your way through the assembly process and is much more efficient method than the stumble method. Be very careful and pay attention to detail when connecting the wires as if you jump the wrong two together you could short out the board ending your assembly on the fast train.
Some wiring can be confusing such as with the board we were using. As you can see the wires mainly connect from left to right but the hard drive LED and the Key Lock wires connect from top to bottom but still show where the (-) connection is. This is where you need to pay close attention to where things actually connect to the motherboard as many boards have similar configurations.
