All you need to do is pick a set of two contacts that will change (open / closed) when the switch is open or thrown.
You have several choices
Use pins (2 and 4) or pins (2 and 3)
That’s only on one side
You still have two on the other side!
Use pins (5 and 6) or (5 and 7)
In each case it does not matter which pin gets connected to the AIU channel and which gets connected to AIU ground.
All that matters is that the circuit is completed / shorted. Or the circuit is open / not connected/