Epson EPL-N2000 Reference Manual page 54

6. Align the hooks on the printer with the holes at the bottom of
the Duplex Unit.
7. Attach the Duplex Unit to the printer, making sure the
connectors and screws enter the proper holes.
c
3-10
Options
Caution:
Do not take off your hand until secure the Duplex Unit with
the screws that came with the unit. Because the Duplex Unit
may come off the printer, and damaged.