Hello. I recently purchased a Dehaven Junior Cinderella stove. The previous owner had never used it so couldn't explain how the parts at the bottom of the "firebox" work. One picture shows a grate, a plate and something I can't figure out. The grate fits at the bottom and the little handle comes out the side hole. It's not very stable though, easily tilting side to side and falling into the ash pan. The plate fits above the grate and prevents air flow through the grate. I don't know what the third object does. Can anyone explain this please?