Picture says a thousand words here.
Google 8 wire stepper motor.
You'll see that you're dealing with 4 coils.
2 wires each coil. You're trying to wire 2 of the coils in series (of course they have to be the right ones).
Now you're left with 4 wires, right? Sketch it out as we go here, it'll make more sense.
2 of those are going to be your "A" and 2 will be your "B".
Draw a capital L. Put the A on the vertical, and the B on the horizontal. That's the way they are usually shown.
The colours of the wires are usually manufacturer specific, so you'll want to find there site. You CAN meter everything out and figure it out... but... It's not that easy to wrap your head around if you've not done it before.
Anyhow - that all make at least a bit more sense now?