IBM 1800409-001A - Manual (Page 171)

6. Insert a single sheet of media, printing side up, with the top
edge leading into the printer, in the manual feed tray (fig. 5.3)
until it reaches the rear of the tray inside the printer and lies
flat.
If you’re printing envelopes, load the envelopes printing-side
up, so that the flap side will be on the left when the envelope
is pulled into the printer.
7. Through your application, print your document.
Fig. 5.3 Insert a Single Sheet
Chapter 5
P r i n t M e d i a a n d D a i l y O p e r a t i o n s 5 - 5