NEC Express5800/320Fd-MR N8800-123F, EXP320K User Manual page 467

5.
Remove the riser card from the motherboard.
6.
Insert optional PCI boards into the two PCI slots
of the riser card.
7.
Remove the bracket cover (for two slots) from the PCI
bracket.
IMPORTANT:
Carefully keep the removed PCI bracket.
8.
Install the riser card on which the PCI board is installed
on the motherboard.
System Upgrade 8-33
Bracket Bracket Cover