How does one make a soul?

In this week’s Parsha we are introduced to the first patriarch of the Jewish people, Abraham. God tells him to leave his father’s house, his relatives and his homeland.

So Abram went as God had spoken to him and Lot went with him; Abram was 75 years old when he left Haran. Abram took his wife Sarai and Lot, his brother’s son, and all their wealth that they had amassed, and the souls they made in Haran… (Breishis/Genesis 12:4-5)