Dell OptiPlex 7070 Ultra Setup And Specifications page 17

6. For installing QR to VESA bracket for E-Series monitor:
a) Align the screw holes on the QR to VESA bracket with the screw holes on the monitor.
b) Install the four screw spacers and the screws to secure the QR to VESA bracket to the monitor.
c) Align and insert the QR tabs on the stand into the slots on the QR to VESA bracket on the monitor.
d) Tighten the thumb screw to secure the stand to the QR to VESA bracket.
Set up your OptiPlex 7070 Ultra 17