Unable to configure a simple IEC connector with an illuminated switch
Take a look a page 2 of that document and you’ll see this:

This says to me that you want to connect the hot input to pin 1, your load to pin 2 and neutral to pin 3 to complete the circuit for the light.

Now as for which pins are 1, 2 and 3, that’s not clear but take and ohmmeter and check to see which pins open and close with the switch: those are 1 and 2. If the light stays on even with the switch open, you have 1 and 2 switched - easy to fix.