Remove a section of the insulation.  

Pick a spot in the middle of the USB cable and use a sharp knife to cut through the outer insulation only.  Make your cut about the same length as the PowerBoost PCB.  Then peel back the insulation to expose the braided shield.

Separate the wires from the shield

Cut away the insulation and separate the shield wires to expose the wires inside.  If there is a foil wrapper around the wires, remove it.

The Red and Black wires are the Power and Ground wires.  The White and Green wires are the Data wires.

Cut and Strip the Power and Ground Wires

 Cut the power and ground wires.  Strip off about 1/4" of isulation from each side.  Leave the white and green data wires intact.

Solder the 'A' side wires:

These are the inputs to the PowerBoost.

• Red to USB
• Black to GND

Solder the 'B' side wires:

These are the outputs from the PowerBoost.

• Red to 5Vo
• Black to GND

Insulate the bare wires

Fold a piece of electrical tape over the bare shield wires.  This will prevent any short circuits from the bare wires.

Secure with 'Zip' ties

Fold the insulated shield wires down on the back of the PowerBoost and secure the ends with 3" 'zip' ties and trim the ends.

Test it

Plug in a battery and make sure that everything is working.