To use the USB charger insert the USB plug into any available USB slot on your computer, then screw the empty battery on to the thread at the end of the cable until  the light on the USB plug turn a steady blue, do not screw the battery all the way to the end of the thread, only enough so that the USB plug light turns blue then leave to charge, when the blue light goes off on the USB plug the battery is fully charged and ready for use.