Pin one is almost always "down" or "left" on the board, if you were holding it upright in front of you. By upright I mean the side that fits the back of the case to your left. I can't remember seeing a modern desktop board that deviated from this pattern. A USB header has two rows of pins which are the same upper and lower. Sometimes the 2nd row omits the shield ground pin, so there would be a total of 9. Pin one would be the one to the left (either one), and your colors would go red, white, green, black, (then shield if you have it, black) This would be left to right or bottom to top, depending how the connector is laid out. Both rows are the same, but don't mix the wires from two different connectors on one row.