Our universe started with the big bang, that is the furthest we can see back in time so we don't know what there was before that. This is how everything became to be after that:
1. Big bang
2. particles start to form
3. smallest atoms start to form
4. the universe is now hydrogen and helium and gravity starts to pull these atoms together
5. when huge amounts of hydrogen is pulled together by gravity the pressure gets so high that fusion reaction starts to happen
6. stars are formed by fusion of hydrogen
7. fusion is the reaction when 2 atoms are combined into a single bigger atom atom, this releases huge amounts of energy, hydrogen fusion creates helium, helium fusion creates carbon etc. so the result of fusion is always a heavier type of atom than the 2 combined atoms
8. if a star is big enough the helium fusion will start when nearly all of the hydrogen is gone.
8.1 in these huge stars other substances begin the fusion reaction as well and more heavier atoms (such as iron) are formed
8.2 star explodes and shoots out all the heavy elements
9. heavy elements, like iron, are pulled together by gravity, slowly creating planets
10. these planets are round, usually a little eggshaped because gravity pulls in to a ball
11. fast forward to earth
12. earth has the necessary conditions for carbon based life (liquid water)
13. carbon based chemical reactions happen spontaneously and randomly, and at some point, RANDOMLY, the first carbon lifeform is created
14. life starts to evolve, slowly from single celled organisms to multicelled organisms
15. life evolves way more into fish
16. fish evolves way more into reptiles which then again evolve into mammals and then life evolves into humans
so in essence everything just became to be after the big bang. everything on earth was based on random chance.
i still have to explain how dust and water became to be:
dust: the dust you see inside is your dead skin mostly, the dust you see outside is rock, which has come off a bigger rock because of wind
water: as i told you hydrogen is very common, the most common element in our universe actually and when hydrogen reacts with oxygen (burns) they form water and release energy at the same time.
if you buy hydrogen gas and burn it you will get water.
PS: this is a quick explanation and most likely i have some mistakes, if you find one please correct me