Apple Power Macintosh 7600/120 Series - Manual (Page 156)

6 Being careful not to touch the sharp edges, pull out the port access cover behind the
expansion slot you want to use, and set the access port cover aside.
7 Remove the card from its static-proof bag.
Hold the card by its edges to avoid touching the connector.
Connector
(back of computer)
Push the port access cover in gently with the finger of
one hand while pulling it straight up with the other hand.
145 Installing an Expansion Card