wiring geckos to stepper motors - common wires to where?

I am wiring the gecko drives with stepper motors with 8 wires. The
unipolar wiring requires connecting 2 wires together and these are
labelled common. There is on pair for each phase. Where do the
common wires from the motor go? I have a common from the Gecko drives
for each motor that goes to the Campbell board but I don't believe
that is where the wire from the motor goes. Perhaps these wires
labelled common just connect together at the motor and do not go
anywhere else?

Thanks,

Keith Clark