I second the voltmeter suggestion but I also notice two "Barrel shaped" electroinc components in the box connected end to end.
These devices have a sliver band on one end In both cases the band is on the RIGHT side as it's photographed.
These are reverse polarity diodes. designed to SHORT the leads if you hook up to a battery backwards and blow the fuse.. So the banded end needs to be POSITIVE or they conduct and pop-a-fuse.. be sure to fuse 'em.
But by all means confirm this by use of a voltmeter cause.. I've seen diodes marked backwards.
