SBUS into ch 1

my rx has an SBUS/PPM out and I put that into ch-1 with the jumper on s-2&3. And I get nothing for radio signal coming in. I did have the channels set for each individual use in MP. Do I need to change them or another parameter to make this work? I don’t get it. Any help?

hardware: RMELIC UHF module and receiver, WFLY WFT09s radio, APM 2.6 autopilot.

it worked in pwm mode connected to each channel but not very smooth.

As far as I know SBUS does only work with Pixhawk, and not with the APM Hardware 2.6, 2.7, 2.8, 3.1. Correct me if I am wrong.

Connecting a PPM Sum Receiver
PPM receivers transmit all the channel information above through a single port (some will transmit additional channels – for example the FrSky D8RSP receiver outputs 7 PWM channels, while in CPPM mode it will output 8).

On APM2 you can use PPM input by putting a jumper on the RC inputs for channel 2 and 3 (just the signal pins). PPM input from the receiver should be fed into channel 1.