Can anyone tell me how to charge the batteries in the Black Diamond NRG Rechargeable Battery Kit. Seems like there is some parts missing

I can't see if you have parts missing or not, so I'll tell you how if you've got everything. Once you've got the AC plugin adapter set to your correct country style outlet, plug the other end into the battery pack on the headlamp that's located underneath the headlamp strap where the cord from the front light connects to the battery compartment. Look for the little grey plastic plug there, lift the grey plug out and connect the charger in there. Hopes this helps.