The view (previous) is simplified, but also first shown as the 3PDT Switch, that it is. Next, is the particular details for this network, of series connected switch boxes.
The layout, for the switch segments, (A, B, C), is non-trivial, very confusing in a 3-D way. So I'm up to it, haha...
For reference, consider the 3-layer switch as a '3 floor apartment':
Say, you lived on 2nd floor, each floor has two apts.
" To RESET the relay switch, " you'd say, "...go upstairs, and down (to Apt 3b)."
" To SET, the switch, that's right next-door" (apt 2b).
At any rate, a 3 layer switch assembly, is not that hard to assemble. A simple pulse exchange, or opposing phases, gets the network access done, and proceeding at the next 'station', each two pulses, does that phase pair, each per station.