Where does the money come from that banks "loan" out?

Can you lend money that's not yours? Isn't that what banks do?

They say that when a bank collects a deposit, that that money (or 90% of it) is then "loaned" to other people. How is it possible for someone to "loan" someone else's money and then collect interest on it for their own personal profit? They never owned the money in the first place.

On top of that, banks don't even use the reserves for loans - they create the money "out of thin air" using the loan application as a negotiable instrument, i.e., it's the borrowers credit that created the money. Again, the banks themselves didn't "loan" anything.

Talk about conspiracy!