Connect tacometer to 2022 Mercury 25-30HP EFI outboard on boat

Connecting an inexpensive tachometer to a 2022 Mercury 25-30HP EFI outboard on boat
PROCEED AT YOUR OWN RISK CHECKING WITH A DIGITAL VOLT METER AS YOU GO.
Electronic tachometer connections with no manual Chinese instructions and no help from the dealer.
Instead of buying $100 special cable that is just a connector on one end and individual wires on the other end, I just cut off the connector on the main engine control cable, the one labeled "gauges" and then connected the individual wires to the generic tachometer wire by wire. "Switched" wire to feed the tack, the "ground"/negative wire and the GREY "signai" (in this case)
PROCEED AT YOUR OWN RISK CHECKING WITH A DIGITAL VOLT METER AS YOU GO.
00:00 Introduction
00:46 generic electronic tachometer
01:52 Figuring out which wires go where
04:14 "programming" - good luck!