How to build it?

[captain harlock]

Enough of that, people. I guess I have to go through problems if I want to become a real hobbyest. Well, about the differentials, could you please tell me, in your own wording, how to build it? I managed to put it together, but I dont know about those red O rings. Where do they go? the big ones works like an oil sealer where you put it around the edge of the diff's case. Right? do I have to use it on both sides of the case? What about the small ones?!!