do you know what make of motherboard you have ? usually (looking at the installed mobo) the front panel headers are located at the bottom right of the motherboard.
But depending on the manufacturer each uses their own layout, though often they are marked on the surface of the motherboard.
If you are asking about polarity, usually the white wire goes onto the negative marked pin. Having said that, the power and reset switches are not polarized. It will not matter how the leads are oriented. The LED leads are different. White goes to the negative pin. After the LED's are connected, if one does not illuminate, simply reverse the leads.