VIPowER USB 2.0, 5.25-inch External Enclosure VP-6228T User Manual page 11

Step5.
a) Make sure the the 5.25" IDE device's front face panel or the
MobileRack's front face panel should be flush with the front
corners (positioned in front of the guide flanges) of the bottom
enclosure cover.
b) Align the 5.25" IDE device or the Mobile Rack mounting holes
with the mounting holes on the bottom cover and secure with four
drive retaining screws (two on each side).
OR
VP-6228(T) USER MANUAL 11