14 billion years ago, the universe started with a singularity
Composed of a single atom, a hot, dense point, it. After 10^-34 seconds of it being in existence, it rapidly expanded faster than the speed of light, bringing everything as we know it into existence.
Since then, the entire universe has been expanding. similarly to a ball that was thrown at the big bang, and continues to accelerate faster. We know this due to seeing red-shifted astronomical objects, indicating movement away from earth