HP Deskjet 6122 Color Inkjet Printer - Manual (Page 20)

The slots for letter width paper are in the sides of the lower
tray. Set the width to LTR to use legal-sized paper.
1. tilt the fence forward 2. insert the fence into the appropriate slots 3.
tilt the fence back until it snaps into place
4. Set the paper length guide by pulling it until the arrow lines up with the paper
size.
1. align the arrows
3. Set the paper width fence by carefully snapping it into the slots for the paper size.
For legal-sized paper, pull the length guide out beyond the
edge of the tray, load the paper, then slide the length guide
against the edge of the paper.