If you remove the faceplate of the Master Socket at the back of it will be six connectors. There should be a Blue wire with White rings connected to connector 2 and a White wire with Blue rings to connector 6. The Orange & White pair and the Green & White pair should not be connected.
Those wires should go to first extension where they are connected to 2 & 5. Another pair of Blue & White at the extension should be connected to 2 & 5 which go off to the next extension, etc., etc. This is called "daisy chaining".
T, March 2009