Unless Channel Re-mapping is disabled, the radio model's channel order must match the Expected Channel Order of the MULTI-Module, which is AETR by default. See the Channel Order page for more details.
The DSM protocol configuration used on the transmitting radio is detected and matched automatically at bind time.
The Channel Assignment table assumes the MULTI-Module's default Expected Channel Order, AETR, is being used on the radio.
If you have changed the MULTI-Module's Expected Channel Order to something other than AETR you need to adjust CH1 to CH4 accordingly. See the Channel Order page for more details.
0 - Multi
Use the MULTI-module telemetry pin to send the trainer information to the radio.
1 - CPPM
Sending trainer channels to FrSky radios through telemetry does not work since the telemetry lines of the internal and external modules are shared (hardware limitation).
On an STM32 module, and with a simple hardware modification, you can go around this limitation using CPPM to send the trainer information to the radio. For more information check the CCPM Hardware Modification page on GitHub.
Once your setup is complete, and before enabling the internal module, you must check the "Disable Telemetry" box to stop the Multi module from sending any data to the radio and therrfore freeing up the line for the internal module.