when the big bang first started, there wasnt matter. it was just energy expanding. eventually, things spread out enough and the universe cooled down to allow photons to form, and light was born(i think about 330,000 years after initial expansion). then it cooled some more, and other particles formed, eventually leading to atoms.
i think at first it was all hydrogen atoms. they clumped together, creating enough gravitational force so that fusion started. the hydrogens came together to form helium, the second heaviest element. this helium is heavier, and floats to the middle of the star. then the same thing happens for lithium, and all the other elements up to iron. iron cannot be a fuel source for fusion, thus the star runs out of energy to 'burn'. eventually gravity takes over, and the star collapses. then it explodes in a massive supernova. these explosions are the biggest explosions we have discovered in the universe so far(i believe). it is so powerful, heavier elements like gold and silver are produced from the force. that is why these elements are so rare.
this process is what spreads different elements out into the cosmos.
i guess that didnt really have much to do with the big bang haha