With the EMS you wire directly for RPM indication. You do not use “RPM Sensors”.
For the pMag, this is a wire between the EMS and the pMag (see the pMag install manual).
For the mag, this is a wire from the mag P lead (usually at your ignition switch) via a resistor to the EMS. The SkyView install manual has a diagram and recommended resistor value.
Carl