Step 1: Prep the panels
This step is pretty easy but tedious.
Remove the top of the garden lights and expose the screws.
Unscrew the "lid" and set aside (don't throw it away). You should see some hardware (battery connectors, wires, LED, battery).
Remove all the unneeded hardware - this would the battery, the wires for the battery (make sure you don't pull out the panel wiring), battery connector and LED.