Okay, have you finished the book yet? I don't remember exactly now, but I don't want to spoil anything if you haven't finished, cause I think it gets explained later. Basically, think homemade death star superlaser, only not on that bog scale. You got one ship that is the main cental core, and the supporting pipefighters that are supposed to be the focusing beams, so to speak. I think.
I might be able to explain how they worked more, but I think that's what happens at the end of the book.