Seeker4

I really don't understand the process of registering! I have downloaded the stardock central software and installed it. During this process I'm asked for two serial numbers, both of whom are apparently optional, and I can't find a refence to any of them. When I registered my game, using the serial number on the back of my manual (GC2-***) I recieved an other rather long serial number. What exactly am I supposed to do with that? Every time I start