Dell Precision Workstation 340 Service Manual page 32

Expansion Card Installation—Mini-Tower Computer
1 card retention arm
2 card connector
3 expansion card
10. Lower the expansion card retention arm and press it into place, securing the expansion card(s) in the computer.
11. Connect any cables that should be attached to the card.
See the documentation for the card for information about the card's cable connections.
NOTICE: Do not route expansion card cables over or behind the expansion cards. Cables routed over the expansion cards can prevent the computer
cover from closing properly or cause damage to the equipment.
12. Close the computer cover.
13. Reconnect the computer and devices to their electrical outlets, and turn them on.