but dont you need an amp for your sub, is it built in. if your headunits got pre outs, usally etiher front, rear or subs,
but front speakers wire from your headunit, it should be colour coded to your speakers in the door.
then dont use rear parcels and sub toghter unless the rear speakers are protcted as the air from the sub will push them out, and you gonna need an amp to power your subs, amps dont supply power , but amplfier the signal for bigger speakers.
have you got front door speaker wires, what wires you got