How to add the level 5 printer (Mac)
System Preferences -> Print and Scan -> click the "+" button at the bottom of the list of printers -> IP.
Next to "Protocol:" choose "Internet Printing Protocol - IPP" from the drop down list.
Fill out "Address:" as shown in screen shot.
Next to "Print Using:" choose "HP LaserJet 4250" from the list.
A screen should appear where you can tick duplex printing. Do this if you want it, then click OK.