Sony PCG-XG28 Primary User Manual page 76

Attach the right side tab of the Mini Docking Station to the right side
hollow of your computer.
Push the tab into the hollow firmly until it clicks.
When the computer is in System Hibernation mode, System Suspend
mode, or off, skip step 1. If the computer is in System Idle mode, switch to
Normal mode, and then follow the steps below.
Press the UNDOCK button on the Mini Docking Station or click
REMOVE on the Start menu.