Around 50 ohms, I think. I highly recommend that booklet to any beginners wanting to light models up. Two pushbutton switches stick out through the back. When you press both at once, the combined effect gives off an orange yellow glow. Without any electricity going through it, the LED just looks like a chunk of clear plastic.
Kids can make up their own story lines, on what each color is supposed to do.
I didn't bother color coding it. I used a wire-wrapping tool to make tight connections wherever possible. Then I soldered these same connections, then snipped off any excess wire length. I used heat-shrink tubing to insulate the exposed connections. This makes the connections mechanically sound, as well as electrically sound.