Dell OptiPlex E1 Reference And Installation Manual page 115

notches
score mark
)LJXUH  ,QVWDOOLQJ D 'ULYH LQ WKH ,QFK 'ULYH %UDFNHW
To further ensure proper positioning of the drive in the chassis, insert and tighten
all four screws in the order in which the holes are numbered (the holes are
marked "1" through "4").
Align the notches on the front of the drive bracket (see Figure 7-8) with the front
of the computer. Hold the bracket level, and lower the assembly straight down
into place (see Figure 7-9).
bracket
notches (2)
)LJXUH   ,QVHUWLQJ WKH 'ULYH %UDFNHW LQWR WKH 'ULYH %D\
See "Installing an Expansion Card" in Chapter 6.
Installing Drives 7-7