This is a latching relay - it stays in either position without power. A "normal" (non-latching) relay requires that power is applied to hold the contacts in the "operated" position.
If you ground (connect to the negative side of the power supply) pin 3, and apply a short positive voltage pulse to pin one, the relay will move the contact to one position, and applying a short positive pule to pin 6 will move the contact to the other position. It is not immediately clear to me which coil will move the contacts to which position.
EXAMPLE: If you wanted to wire a Power Supply using this relay...
You would wire the positive supply voltage to pin 7, and the load positive terminal to pin 10 or 12. The negative side of the load will be connected to the negative side o fthe power supply. The relay contacts are used in a circuit the same way a switch would be used.