@smilertoo here's mine.
Here is the front camera and from it come 2 black cables, they are both included in the box when you purchase it. One is the power lead that you will take to your fuse box, the other is the USB lead that you will take to the rear facing camera.
My fuse box is in the passenger footwell. This is where I take the first black lead from the front camera. You can see the black cable in my hand and this comes readily split for you. One is for constant power (yelllow, labelled with "battery". One is red, which will be powered when you switch the ignition and is labelled "ACC". Lastly, the black one is a ground cable.
Here you can see the red and yellow power cables crimped into 2x fuse taps. Simply refer to your car manual to identify a fuse that is constantly powered and one that come on with the ignition and use the tap in them.
This is the rear camera, the cable is a little thick but it wasn't too difficult to feed along my car roof lining and into my boot lid where is meets the rear camera that is stuck on the rear windscreen.
After seeing these pics, one thing's for sure, my car is filthy inside and out.