Hi Chris,
Its a little trickier than that but not much. You should download the user manual for the PowerExpander first. Is this an end (side) loading receiver? The wires are too short to work with a top loading receiver. If so, then you need to see which side the power input is on and match that to the power lead on the JR or Futaba PowerExpander. They are on opposite sides of the board for the two. Please let me know if you have any more questions.
Thanks,