Sentra 91 tachometer addition

I have an instrument panel from a nissam stanza which includes a
tachometer and the speedometer is run electrically (as opposed to the
spinning square). I can rewire other wires but what about the
speedometer and tachometer?

For the speedometer I will need a 'speed sensor' which comes with a
stanza. Where do I find it in a stanza? I couldnt follow the wires in
the stanza at the junkyard.