Apple LaserWriter 12/640 PS - Manual (Page 14)

Load three-hole punched paper face down, with the holes toward the left side
of the cassette. Load letterhead paper face down, with the tops of the pages at
the front of the cassette (the handle end).
7 Adjust the length and width guides so that they fit snugly against the paper.
Adjust the length and width guides
to fit the size paper you’re using.
Align letterhead and three-hole
punched paper as shown.
14 Chapter 1