Tying into existing Chimney???

[dmaves]

So I discovered that the stove pipe and chimney on my newly purchases house was in severe need of being cleaned/replaced; I am planning to replace the stovepipe that runs from the wood furnace to the chimney, but after taking it apart I discovered that there was no adapter or tee at the transition of the stovepipe to chimney. The chimney has a rectangle terracotta flue liner and the wood furnace is using round stove pipe. I was just wondering what would the typical process be for tying the stovepipe into the chimney? I attached a drawing showing my application; the stove pipe passes through a basement block wall where it then transitions into the chimney via 10"x10" square hole in the terracotta.