Dell Precision T3400 (Late 2007) - Manual (Page 181)

Adding and Replacing Parts
181
6 Remove the filler bracket to create a card-slot opening, if necessary.
7 Prepare the card for installation.
See the documentation that came with the card for information on
configuring the card, making internal connections, or otherwise
customizing it for your computer.
CAUTION:
Some network adapters automatically start the computer when they
are connected to a network. To guard against electrical shock, be sure to unplug
your computer from its electrical outlet before installing any cards.
8 Place the card in the connector and press down firmly.
Ensure that the card is fully seated in the slot, the top of the card is flush
with the alignment bar, and the notch in the top of the card fits around the
alignment guide.
1 release tab 2 card retention cover
3 card retention door
3 1 2