I’m sure there are lots of different stories pertaining to the creation myths of different Chinese cultures, but here’s one of the main ones I found.
At the beginning there was an egg and for 18,000 years it included chaos and the universe, the primordial man was also in this egg, and his name was Pangu. One day he decided to finally free himself so broke out of the shell and the white part of the egg formed the Heavens, while the rest formed the earth, hence the Yin Yang significance.
Pangu lifted up the sky to separate it from the earth, which also took 18,000 years. There are different versions of the story, and some say he was helped by a turtle, phoenix, dragon and a Qilin (sort of like a mythical unicorn creature)
When he died his breath became the wind, his sweat became the rains, his voice was the thunder and his eyes were the sun and the moon. The stars were his hair and beard and his flesh were the flowers that covered the earth.
After his death the goddess, Nuwa, created man using mud, every drop was a human and they were individually crafted and very clever. However when she god bored of this task she put a rope into the mud and let the drops form into humans, and these weren’t so clever.
There are other creation myth stories from China and more stories that happened after this, but this just the general myth regarding the creation of the universe.