Apple PowerBook (Duo 270C) - Manual (Page 249)

The next four steps describe how to insert the card.
s
Important: Handle a NuBus card by its edges only, and be
careful not to touch the pins inside the connector.
s
10. Lower the card into the slot.
NuBus cards have all or most of their chips on one side. Hold
the card so its chips are facing up, and the connectors on the
card and the slot are aligned. You may need to tilt the card as
you lower it into the slot.
11. Adjust the card so its connector lines up with the
connector on the slot.
Don’t press the connectors together yet.
continues .
Align connectors
Connector
Chapter 13: Building a PowerBook Duo System 233