The statement under should of course say "hole", albeit in some devices it is actually a small vertical slot. "insert a thin pin like rod into the SLOT"

Although I cannot say for 100% certain if it definitely applies to your model, but with DVD / CD units in general if you "carefully" manually pull down the "casing" front flap door to reveal the front of the disc tray behind, somewhere along and just under the bottom of the slot you should see a small hole, this is the manual over ride, insert a thin pin like rod into the slot and push and the tray should open.