For a Mac,

System Preferences -->
    Printers & Scanners -->
        + [add] -->

and in the Add pop-up,

IP ( not Default ) -->
    Protocol = HP Jetdirect - Socket
    Queue    = (leave blank)

For Windows with AD (most or all PCs),

file explorer -->
        and look for names starting with SPSY
        mem prnt srv -- suggestions welcome  
        on how to make that memorable. R before V?

For Windows not on AD (any machines left?),

start button -->
    devices & printers -->
        add a printer -->
            add a network printer -->

Browsing and discovery may well fail, or yeild too many choices to parse, and the job becomes semi-manual.

the printers

The third floor Xerox
Xerox AltaLink B8145
five trays
global integrated office finisher

The psych office Xerox
Xerox AltaLink B8145
five trays
office finisher

The biotech printer, in BT2012
HP LaserJet (Pro?) M402dn

The colour laser in the psych office
HP LaserJet 400 color M451dn

drivers (if needed)

Downloads from Xerox.

generic drivers

When a specific driver is lacking, you can treat a printer as a superset of some older one. You might loose the use of the Xerox stapler – no worse than that.

For example,

HP LaserJet 4000 (Mac or Windows)
HP LaserJet 4050 (Mac or Windows)
Generic PostScript Printer (Mac)
Generic PCL (Mac)
Generic / MS Publisher Imagesetter (Windows)