The red wire from the light is connected to the output on the switch and to the hot terminal on the light at the other end. Or perhaps a fancy ceiling light you want to show off in the living room? At the outlet, the travelers are spliced to run to SW2 using the red and white wires in that cable. Now by understanding the diagram above, go up to the top diagram and by using the concept shown here, just use your mouse pointer on that diagram and follow the flow from black wire hot wire to the load and return through the white wire neutral. Cut in between and connect your nth switch.
Then, you would have to connect one black wire and one red wire from the first switch onto your third switch; screw the black wire on the top terminal and the red wire on the other side, also on the top terminal.
How to Replace a Light Switch
Emma Clark Hey there! With this arrangement, two lamps can be plugged into the same outlet and each can be controlled separately from two different locations. The cable consist of a black wire, a white wire and a bare copper wire. The source is at SW1 and the hot wire is connected to one of the terminals there. And this site to explore more methods for 3-way switching. The white wire is mark black on both ends to identify it as hot.