Follow the Adafruit learning guide to solder the solar charger.

You need to desolder the 10K surface mount resistor from the THERM pads and solder in place a JST cable with Female port.  I cut one of the JST Battery Extension cables in half and soldered the female end to the solar charger board.  Solder the male end to the 10K Thermistor wire.  Be sure to use heat shrink tubing!  This will allow you to run the thermistor wire into the project box from the outside and easily disconnect when you want to remove the board from the box.  

Also, I recommend solderinng a 2.2K resistor over top of the PROG surface mount resistor for about 950mA of max current draw. This will let you take full advantage of the solar panel!  Use a good amount of solder to solder the solar charger board to the printed circuit board header stands.  You will also want to solder together two JST male wires (red to red, black to black) for connecting the solar charger load female port to the Flora power female port.  The battery port shown here is connected to a rechargeable battery using the second JST Battery Extension Cable.