I'll describe your picture to keep it easy to understand...
the terminal on the left is the common terminal. Your power feed for whatever equipment you are controlling will connect to that terminal.
The top terminal on the right is your NC (normally closed) terminal. When the relay is in its de-energized state, the contact is closed; i.e. your equipment will have power supplied to it. When the relay is energized, the contact opens; i.e., your equipment will not have power supplied any more.
The bottom terminal on the right is your NO (normally open) terminal, and is typically the terminal that you will use. It operates the opposite way that the NC terminal does. When the relay is de-energized, your contact is open; i.e. there is no power to your equipment. When the relay is energized, the contact closes, giving giving power to your equipment.
The wires on the bottom of the relay are already soldered to the coil terminals. there are also points on the bottom to solder to for the COM, NO, and NC terminals.