Acer AT310 F1 - Manual (Page 72)

3 System upgrades 54
6 Install the expansion card.
(1) Lift the PCI slot lock securing the slot covers of the expansion
slots.
(2) Pull out the slot cover and store it for reassembly later.
Caution: Do not discard the slot cover. If the expansion card is
removed in the future, the slot cover must be reinstalled to
maintain proper system cooling.
Remove the expansion card from its protective packaging,
handling it by the edges.