Dell D02T Installation Manual page 13

8 Fasten the two (#6-32x1/4) screws to secure the rail on the top of the system chassis.
9 Fasten the three (M5x6) screws removed from the rail in step 6, to secure the rail to the system.
10 Align the screw holes on the other rail to the screw holes on the bottom of the system and fasten the remaining three (M5x6) screws
to secure the rail.
NOTE: Removing the bottom cover is not required to install the rail to the bottom of the system.
Rack rails 13