HP 24SII - Manual (Page 133)

5. Hold the memory expansion module in your hand so that the
card edge connector is facing down.
IMPORTANT: On the memory expansion module, Pin 1 is marked.
Pin 1 should be positioned to the left of the unit (with LEDs facing
you).
WARNING: If module is plugged in backwards, it will be damaged and
become inoperable.
6. Line up the connector of the memory expansion module with
the socket. Push down on the memory expansion module until
it is firmly seated in the socket.
7. If a memory expansion module needs to be removed, pull
straight up and away from the socket.
8. Once memory expansion has been completed, replace the
cover of the unit and the 4 phillips-head screws that hold it.
Apply power to the unit. The upgrade is now complete.
9. To verify memory upgrade, enter the configuration mode (see
Section 8 ). The installed memory will be displayed in the main
configuration menu.