Epson AcuLaser C8600 Reference Manual page 218

8. On the back of the printer, slide the upper cover down and
open the lower cover.
9. Connect the two sets of connectors respectively. Close the
cover.
10. Reattach the left connector cover.
11. Plug the printer's power cord into an electrical outlet.
12. Turn on the printer.
To confirm that the Large Capacity Paper Unit or the 500-Sheet
Paper Cassette Unit is installed correctly, print a status sheet. If
the unit is not listed on the status sheet, make sure the electronic
connectors connecting the option to the printer are connected
securely.
216 Using Options