#1
the diagrams I've found don't make sense to me.

I have a jack soldered to a + and - wire.

then, I have a separate wire with a + and - crimp on each end.

so the + and - from the jack goes to speaker 1, and then the +/- on the other wires go from speaker 1 to speaker 2.

is that correct?
#2
Run the positive wire from your amp to the + of the first speaker. Now, run another wire from the + of the first speaker to the + of the second speaker.

Run the negative wire from your amp to the - of the first speaker. Now, run another wire from the - of the first speaker to the - of the second speaker.

You just wired them in parallel and you have a combined impedance of 4 ohms, provided the impedance of each is 8 ohms. If the impedance of each is 16 ohms, you now have a combined impedance of 8 ohms.