How do I clean a Century woodstove?

I have a Century brand wood-burning stove which has an upper plate inside the burn box which is supposed to reduce the ammount of smoke that goes up the chimney or something or other-however, even the owners manual does not come with instructions on how to remove it for cleaning (when I clean out my chimney from above, the soot is falling down on top of this metal plate and I'm not exactly sure how to get the soot out from the top of my woodstove. Does anyone have a century woodstove who has encountered this problem before and how did you go about resolving it?