Sorry for the crude markup. The galaxy only needs two wires, so ignore the yellow and white.
Take two 1k resistors from the panel ancillary pack and twist two legs together.
Remove the blue wire from the silver terminal and place wire it with one of the untwisted resistor legs to one of the spare copper screws.
Place the two twisted legs under the silver terminal and tighten.
Take the other spare resistor leg and place it under the same silver screw terminal as the green wire.
Now the zone should read 1k when closed and 2k when open.
At the control panel side, wire yellow to the zone and blue to 0v (the middle connection for each zone pair).
To check everything, enter menu 21 Display -> Zones and then press the hash key to show the resistance is around 1k door closed and 2k door open.