The conductors are connected at the switches and the leds. An additional ground wire will be needed. The bottom left led lets you know you have a completed circuit. The led above it lets you know the tool is working. The other leds are on the other end. If you are making a new cable then the two halves can be beside each other. If you are testing an installed cable then you have to verify both ends anyway. If one switch powers more than one led then both conductors are shorted and should be cut away. If a conductor fails to light an led then it should be cut away.
