Installing the Envelope Tray Use the following procedure to install the envelope tray: 1.   Remove the 500-sheet paper tray from the printer and store it for future use. 2.   Unpack the envelope tray. Note:   Save the packing material for future use. 3.   Slide the envelope tray into the paper tray support unit until it clicks into place. 4.   See “Loading Envelopes into the Envelope Tray” on page  42 for instructions for loading envelopes and postcards into the envelope tray. 5.   From the Paper Menu, set SOURCE to ENVELOPE to use the envelope tray as the source tray, and set ENVSIZE for the selected envelope size (see “Selecting 142 User’s Guide