Solder socket headers to the FeatherWing Doubler and plug headers to the Feather RP2040 and the Adalogger FeatherWing.

Tin two pieces of silicon wire. Solder these to two pins on the slide switch.

Add heat shrink to cover the switch's solder connections.

Solder one wire to the EN pin on the FeatherWing Doubler. Solder the second wire to GND on the FeatherWing Doubler. This creates the on/off switch connection when you plug in the Feather RP2040.