CorrectKoalar's image is the injector top with hair pin clip removed. Press the top down and replace the hair pin.
They might not all be the same
I suspect if @jose hunt does not recognize the picture we need a photo of the leak before we can get anywhere
The routing variesHas the fuel piping been fitted incorrectly? The feed from fuel tank should go direct to the diesel filter. Return from injectors etc goes straight back to the tank. Maybe you connected the lift pump to the fuel return line.