Synology DiskStation DS2419+ Hardware Installation Manual page 15

b Use two fingers with firm, even pressure to push down on the card and the bracket.
c Push back the clip to secure the newly inserted card.
Note: Make sure the connectors are fully inserted. Otherwise, the network interface card might not be able to function
properly.
5 Replace the top cover, and then replace and tighten the 2 screws you removed in Step 2.
15 Chapter 2: Hardware Setup