Dell Dimension 2200 - Manual (Page 75)

Adding Parts 75
7 Align the cutout on the bottom of the card with the crossbar in the
system board connector. Gently rock the card into the connector until
it is fully seated.
If the card is full-length, insert the front end of the card into the
corresponding card guide at the front of the computer as you insert the
card into its connector.
card cutout
card
card connector
on system board
crossbar