Nothing there.........................
That is the PRE-BIG BANG Theory.
The Universe was created not by adding everything to nothing, but by removing something from everything.
Removal of anti-matter created an imbalance, chaos, disorder, destruction. The Imbalance left matter whose purpose is to balance everything again. That matter is our universe. The imbalance is what gives our Universe energy.
When the balance is restored, the energy dissipates, the matter returns to ZERO because matter and anti-matter have equalized and we are back to the PRE-BIG BANG.
We have attempted to achieve this balance by trying to reduce the temperature (vibrational energy) of a particle to absolute zero, but we cannot. That's because it would take all the energy in the universe to do so. If we succeeded the universe would cease to exist(including us), Leaving us with an answer that no one would ever know.
Ergo the reason we can never get an answer is that we are asking the wrong question.
The question "how?" does not matter. The question we should pursue (and which will work out much better for us) is "why?".
To summarize: If the universe(matter) was created from nothing, then nothing in the universe matters.