usually the usb connectors for the front or top hubs are located at the bottom of the board near the middle, they will have print on the with like USB097 USB### and so on, next to that to the right corner bottom is where all the cables go for your LED lights, and Power/Reset Switch.
the motherboard manual will tell you exactly where they go and the back of those cords usually have a down arrow on the + side and those usually go on the left pin of the set.