Connecting electrical wires on a central vacuum

Hi !
I have a Kenmore central vacuum (model # 34326), 3 inlet valves on different floors. the inlet valves on the second and third floors are already connected. I need to connect the inlet valve located in the basement near the vaccun cleaner.
There is one cable on the third floor with 4 wires, black and red on one screw and yellow and green on the other. This is OK.
There are two cables on the second flloor, The black and red wires of the two cables are connected together on the same screw and the yellow and green wires of the two cables are connected together on the same screw. This is OK
I have two electrical cables in the basement one has a red and black wire and is directly connected to the vaccum. The other coming from the second floor has a red,black,green and yellow wire and must also be connected to a central vacuum inlet valve.
I must attach the wires to two screws located on the inlet valve but I can't seem to figure out how to connect the different wires together.
Thanks for your help.
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