This is one way in which the scheme could work:

1. You put your own property (home, car, piece of land) as a collateral and get a loan from a bank.

2. You use the money to buy a property that you expect will rise in value.

3. You sell the property, pay back the loan and get the profits.

So yeah, $0 of your own cash invested. But if the property doesn't rise in value, you may end up losing the collateral.