First, the system must be configured to authenticate with the letnet Domain. You do this through Directory Services.
Once logged in with an Active Directory Account, go into System Preferences into Print & Scan.
Part of using a network printer on a Mac requires that you store your password in Keychain. If you do and you change your network password, you'll need to go to Keychain (Applications/Utilities) and look under letnet to change your password.
Be sure the system is unlocked as administrator, if not click on the lock at the bottom.
Select the + and click on Add Other Printer or Scanner...
If configured correctly to be on the letnet domain, you should automatically see all of the printers at LETU.
Find the printer you are looking for, in this case a printer in IT.
Select under Print Using the Select Printer Software...
Find the correct printer software, in this case we found the Canon imageRunner driver.
Click on OK and back at the Add Printer dialog, click on Add to add the printer.
You may be prompted to key in your password and add it too.