Brother HL-8050N - Manual (Page 45)

2 - 12 USABLE PAPER TYPES AND PRINTING METHOD
Load Paper Larger than A4/Letter Size in the Paper Tray
Follow the steps below to load paper larger than A4 or Letter size into any of the paper trays.
(Paper tray 1 is shown in the illustrations.)
1
Place the paper tray on a flat surface.
2
Remove the lid of the tray.
3
Slide the right and left lock tabs in the paper tray outwards
to unlock them.