Biologally speaking, you have 2 parents, 4 grandparents, 8 great- grandparents and so on. Each generation you go further back the generation of ancestors double.
After 31 generations you have over a billion ancestors. 32 teers back you’ve got 2 billion. That was more than the human population on Earth at the time.
Most of our ancestors had more than one child.
This means we are all related to each other.