Dell C3760dn Color Laser Printer User Manual page 352

5 Gently lift the printer off the optional 550-sheet feeder, and place it on a level surface.
WARNING:
Two people are required to lift the printer.
6 Insert the tray1 into the printer, and push until it stops.
CAUTION:
Do not use excessive force on the tray. Doing so could damage the tray or the inside of the printer.
7 Re-connect all cables into the back of the printer and turn on the printer.
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Removing Options