As others have pointed out this has nothing to do with evolution. However, some (many?) of us also hold an atheist worldview, and this question is a valid challenge to that.
The answers are: we don't know, and we don't know respectively.
A slightly more meaningful answer is this; the standard model explains some but not all of the the properties of physical entities, I imagine in the coming years we'll construct a model that explains more, and eventually all of these properties.
The 'stuff' for the big bang. Don't know. My prefered answer is nowhere. Your question only makes sense if the big bang is viewed as a change, since time came into existence with the bang, there is no before the bang, so the big bang has before to have changed from. This is a wild guess however, and no doubt those more up to date with the latest findings of astrophysics will mock it.
As Dawkins pointed out any being capable of creating the universe must be more complicated than the universe, and thereby more in need of an explanation.