Apply a small amount of flux to the surface mount pads on the board.

Recommended: for additional strength you may want to consider gluing the button in place. I did this on my fix.

Secure the button in place on the motherboard making sure it is flush with the circuit board and touching the surface mount contacts. One-by-one heat each of the J Leads on button using your soldering iron. If you've done this right the flux should draw the solder to the SMT pads on the board.

Testing: to test your soldering job you can carefully screw the motherboard back in place so that the battery contacts are touching the motherboard. Gently press the button being careful not to break it. If your soldering was done correctly you should hear the fan turn on when you power it up.

Using a toothpick apply a drop of epoxy for each of the J leads on the button to circuit board so that the drop covers the lead. Allow the epoxy to cure based on the product instructions. The epoxy helps keep the button in place so that when you press down it doesn't break free from the board.

Note: The button harvesting process may cause some flux to get into the button and it may not click when you press it. This happened to me. I was unable to find a way to clean the button without damaging it. Unfortunately you may find the button requires additional pressure in order to power on and off your device.