Hey JB; The "normal" method of connecting two or more pickups together on most guitars is parallel. Pretty much any wiring diagram will show that.
On the other hand, if you're talking about connecting one humbucker, onto itself, in parallel, its black & red wires together to "hot", and green & white wires together to ground.
Parallel would use only the first switch, when that switch is in the "down" position. That is, the black/red wires shorted together, and the green/white wires shorted together.