If you are not using a CSE managed Linux workstation, add the printer for your department, substituting letterhead.cse.umn.edu for cse-print.ad.umn.edu as the name of the print server. Available print queues:
Print the file to the print queue for your department
Check your University email. An e-mail with the subject Letterhead containing a PDF of your document with letterhead added to the first page should arrive.