I am trying to understand how the beginning of the universe unfolded. I've tried to read up on it, but some specific questions never seem to be addressed. What is the stuff that is in the beginning of the universe? I commonly read that it's just "energy," but what is energy in this context? Also, isn't each fundamental force associated with a boson? Does this mean that in the beginning there was fundamentally one type of boson, and after the fundamental forces split, there came to be four bosons? Also, where do quarks and leptons come from? If the beginning of the universe was just energy, how do two distinct forms of matter, quarks and leptons, come into being?