At first, look at this wiring picture, notice the  sensor 'E' and 'F', they work when the braking light is on.So please don't mix that.

 

Installation is very easy, the sensors and display just plug in to the main unit with only 2 wires to connect to reversing light!
A fitting kit and hole cutter drill bit are supplied as well as installation instructions.

What tools are required? 
All you will need is an electric drill to drill the bumper and screwdrivers to remove any interior panels to access the reversing light wiring and to hide the cables.

Where should the sensors be positioned?
Sensors should be spread evenly in a horizontal line across the bumper with a gap of between 30cm and 40cm between each sensor and
 at a height of between 50cm and 80cm from ground. Make sure no parts of the vehicle come within the detecting range (Horizontal 80 degrees, Vertical 70 degrees),eg. towbars and rear mounted spare wheels.