Sony PCG-XG28 Primary User Manual page 75

Connect the Mini Docking Station to the docking/floppy disk drive
connector on the back of your computer.
When a charged battery is inserted in your computer, you can attach and
detach the Mini Docking Station without turning off the computer.
Open the cover of your computer.
Attach the left side tab of the Mini Docking Station to the left side
hollow of your computer.
Push the tab into the hollow firmly until it clicks.