Dell 23.8" OptiPlex 7410 All-in-One Desktop Computer (Gray) - Manual (Page 40)

Steps
1. Align the stand to the slot with the display-assembly base.
2. Slide the stand into place into the slot on the display-assembly base.
Next steps
1. Follow the procedure in After working inside your computer .
40 Removing and installing Customer Replaceable Units (CRUs)