Atheists believe everything occurs by happenstance and there's no rhyme or reason for humanity's existence. In their eyes there's no real or imagined reason for all that we see about us. To them, 'NOTHING, begat EVERYTHING.'
Nothing begat everything is almost certainly true. Matter and energy are borrowed gravitational energy from the inflation of space-time at the Big Bang. As Hawking has been saying, the laws of science appear to lead automatically to what we see around us in this universe. So there is rhyme, and rhythm: the real mystery for Einstein was in
why the whole universe seems to run according to rhyme and reason, expressed as the laws of physics.
Einstein's god was a metaphor for the fact that the universe can be understood, and Hawking used a similar god metaphor. That's not a real being of any kind, and it's not even a god that kicks things off. The laws of science are the god, and they arise as natural properties of space-time, and work without being directed.
New stars are forming on their own the whole time, just as many stars are disappearing all the time. New planets are forming right now around stars in other parts of our galaxy, and in other galaxies, probably too many to count. A giant star forms from hydrogen, burns its fuel quickly, dies young in a massive collapse and explosion, and that produces the shockwave that pushes more hydrogen together to make a new star, and also provides the heavy elements that go into orbit around that new star. An accretion disc of dust and gas makes solid planets near the star and gas planets further out.
Life starts as non-life, just like it says in Genesis. The first cell is unknown; we really cannot know what it was, but we know our cells today are much more complex and use different biochemistry because genes can be mutated and selected for by the test of survival and reproduction, obviously. Mutation is random but natural selection is very highly directing. Evolution by natural selection is a brilliantly effective ratchet, that increases complexity tiny step by tiny step. If there is life anywhere else in the universe, it will have also arisen by a process of natural selection, which completely explains biological complexity.
Those accounts, from different branches of science, may turn out not to be 100% right. But they won't ever turn out to be 100% wrong. There are major problems even knowing what the universe is made of. But everything from nothing is indeed it: the total energy content of the universe is zero. We live on gravitational credit. If we go into a Big Crunch then it all gets paid back again very quickly. But it looks like there will be only expansion ahead for the universe.
Stuart