Identify the black latch on each of the plugs that are connected to the PBCs.

Swing the black latch open by gently prying the front/extruding lip of the plug with a spudger or other flat tool.

To give a sense of direction, the latch should swing away from you or towards the LED (metallic square).

Grab each ribbon cable and apply a horizontal pulling force (with respect to the LED control PCBs) to disconnect them from the connectors.