Property is the Overall Context
So he hits the other man with his stick, and takes that man's stick. More Property. Then he takes the other man as his slave. (He has both sticks.) Property.
Property is the fundamental concept in both man and civilization. It's not just an artifact strapped on from the outside; it is the defining feature of existence. Everything* else -- including Sartre -- is within the context of property. It can be conquered, captured, or annexed, usually by force. Armies capture land, navies capture oceans, tax agents capture delinquencies. It can be purchased, in some societies, with money or other goods. It can be stolen from other humans or nations by force, deception, stealth, etc. It can be created from raw materials (other property). It can be created from intellectual, artistic and academic pursuits. It can be compiled, from existing data created by others.
So he hits the other man with his stick, and takes that man's stick. More Property. Then he takes the other man as his slave. (He has both sticks.) Property.
Think of the (imaginary) first human. There he stands, on the Savannah, looking around. Just him.
He picks up a stick. His stick. Property.
He sees the Savannah. His Savannah. Property.
Then he sees another Human with a stick. "On MY Savannah!" he thinks.
So he hits the other man with his stick, and takes the second stick.
More Property.
Then he takes the other man as his slave. (He has both sticks.)
Property.
Property can be created in a few ways:
* And by "everything", I include, of course, "nothing".