Cut the wires of the fan shorter and take about 2cm of insulation of. Now unscrew the screws a bit, connect the wires of the fan and screw the screws back in place.

Now take your wire, drill a small hole in the fan and feed the wires through. Now take a bit of insulation of, unscrew the screws a bit, wrap the wires around the screws and screw them tight again. Make sure the polarity is the same as the fan. I used 0,5mm thick wire but after a while it gets pretty hot so make sure you will use at least 1mm thick wire becouse this heater will draw about 7 Amps. You maybe want to take the sticker of the fan aswell becouse it wants to peal of and you don't want it to touch the hot nichrome wires.

Now you can test it by connecting it to a 12 volt power supply that can deliver at least 7 Amps. I used a 17A lead acid battery.

When you connect it the fan should start blowing air and the nichrome wires should start getting hot. If you are not sure if every spring is heating up you can change the polarity. Now the fan won't blow and you can see if every nichrome wire get's orange. Don't do this to long or it will overheat! If not every spring get's hot you can check the solder connections.