NPN or PNP for auto bed levelling

​I have a couple of questions to be cleared about wiring. First of all, as I understood from @mickeypop 's sayings in here:
[www.instructables.com] , S pin of the RAMPS is "Signal in" pin and it needs to take in 5V voltage. PNP and NPN proximity sensors are different basically as the Black wire could be used as "sinking" or "sourcing" the current as mentioned here:
[www.schneider-electric.co.uk]

If the S pin is "sinking" in RAMPS how can we use the NPN proximity sensors as they are used for sourcing cards? Are they different in wiring or what? And is there any difference in voltage dividing of these types? Please could someone clarify this mess in my head?

It's easier to use a 12vdc relay board. Have the sensor trigger the relay and use the relay's switched output on the endstop pins.

most proximity sensors need 10 - 30 volt you are probably using 12 volt the PNP type will source that 10-30v applied on the black output too high for arduino ramps needing 5 volts max thus use method mentioned in the last reply with a relay or feed a 4n25 opto coupler led side with the black through a 1k series resistor and the coupler output to the +5,gnd and signal in on ramps