To replicated original firmware behaviour, the red LEDs are configured as a PWM light and are controlled using
Power4 and the dimmer slider.
LEDs that turn on with the relay cannot be controlled separately.
Unclip the panel from the base. Remove two bottom screws and lift the plastic cover. Pull out the PCB by releasing the 4 clips holding it.
The five needed pins (3V3, RX, TX, GPIO0 and GND) can be easily identified.
After the flash is complete disconnect the 3.3V power and power the touch plate using its base.
It is not needed to solder the wires, just use header pins and make sure there’s contact by applying some pressure.