We dive into this (after a problem with uploading).
This is a look at the structure of the human person, and while it's longer than I anticipated, I believe it is super important. I use the 4 causes of Aritotle to get into this:
The efficient cause: A human sperm and a human egg got our bodies started, but it needed an eternal influence to cause our immortal souls to start. Therefore, we must conclude that God infused the soul at the moment of conception.
The material cause: That's our body!
The formal cause: The soul is the form of the body, it organizes our material elements to be what it is: of human nature. We talked about the powers of the soul, the will, the intellect, the passions, etc.
The final cause: That's next time!