Oil Pressure Sending Units and/or Machanical

[GOPAPA]

Where do you start/end -- and with and what do you use to install a machanical oil pressure guage system.

Where do you start/end --and with and what do you use to install a electrical (dummy/idiot light) system?

Where do you start/end --and with what do you use to install a electrical system showing pounds on a guage ?

Feel Free to Correct me on any of the above .. because correct information will not only help me ,,but help anyone who searches for the right answers .. gp