you first need to determine the voltage output from your NVR.
after that from what i understand you need to power on a flood light running on 220 volts.
for example nvr gives out a 12 volt signal.
so you will need a relay thats rated at 220 volts but with coil voltage rating of 12 volts.
further more, there is ampere rating of the relay as well. for example your flood light is of 500 watts, and working at 220 volts, your ampere requirement is 2.7, so you must use a relay that exceeds this requirement. for example at least 5 ampere rating.
the relay will have 4 pins and would be a normally open contact type.
2 pins will operate the 12 volt coil. when coil is powered up, the contacts of the 220 volt circuit will close and your flood light will power up.
the other 2 pins will be for the 220 volt circuit.
