For the printer directly hooked up to my computer, I just went into System/ Administration/ Printers and added a new printer. It autodetected it, I browsed down the list for the right manufacturer and model, and that was it.
For network printers it is a bit more complicated. If you let the printer print out a status page, it will usually tell you what nnn.nnn.nnn.nnn IP address they are at, with each nnn a number of up to three digits.
Then in Firefox, open up http://localhost:631/admin. Select to create a new network printer and provide the desired info.
For what it is worth, one of the two departmental printers required the info
appsocket/HPjetdirect socket://nnn.nnn.nnn.nnn HP Laserjet P3005 Postscriptand the other
appsocket/HPjetdirect ipp://nnn.nnn.nnn.nnn TOSHIBA e-STUDIO850 series PSYour case may vary.
Something else you want to do: for each printer edit the properties. Then select job abort instead of printer delete if something goes wrong. Then the printer is still set up if you temporarily forget to turn it on.