Oki MB472dn User Manual page 789

3.
Place the machine on the second tray unit gently.
4.
Attach the lock parts.
Remove the left and right covers from the lock holes.
Align the tabs (two pieces) on the upper side of the lock pieces with the holes on the machine.
Insert the tabs (two pieces) on the upper side of the lock pieces into the holes on the machine.
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