Hilchot Berachot 3:9-10 (Pat HaBa’ah B’Kisnin)

In today’s shiur, we learn about the famous concept of Pat HaBa’ah B’Kisnin – a sort-of bread on which we make a Mezonot, unless we are “kovei’a seudah” on it, in which case we make Hamotzi. What is the definition of Pat HaBa’ah B’Kisnin? How do we determine if we are kovei’a seudah?