Help with atx case l.e.d.s, power_Led...Needs as much help as I can get cheers?

Ive recently bought a new motherboard, Biostar Tforce 550 and a Cooler Master cavalier 3 atx case, the problem I'm having, is I cant understand how to connect the front panel power button, and the power_led. The motherboard is a 3 pin connector + + -, but it has only 2 wires coming from the power led, a green one and a white one. I dont want to try and connect them just in case I break something, also which wire is positive and which one is negative, because there not labled... It would be very much appreciated for any help. thankyouHelp with atx case l.e.d.s, power_Led...Needs as much help as I can get cheers?
Green is positive, white is negative. You will not hurt anything by plugging it into the wrong spot, it is just a switch (no power). All switches are two wires, but a few have an empty spacer so that it looks like three pins are used. Most mother boards will accept the negative on pin 2 or 3, so give err a try.Help with atx case l.e.d.s, power_Led...Needs as much help as I can get cheers?
Have a look at the book that came with your motherboard,the coloured wires are the clue.
Consult your motherboard documentation. The white wire is usually negative. My guess based on the info you've posted here is that the first + is for the power switch, and the +- is for the power LED.