Connet the receiver to FC and run the Betaflight. On Betaflight GUI, configure theUART1 port to serial port in Ports tab. Then click the Save and Reboot button in the lower right corner.
In the Configuration tab, for Receiver Mode, choose Serial_based receiver (SPEKSAT, SBUS, SUMD); Serial Receiver Provider, chooseSPEKTRUM2048. And click the Save and Reboot button in the lower right corner.
Type:set spektrum_sat_bind=9 in CLI and save.
Repower the receiver. The light on the receiver will flash rapidly, which means it's on binding mode.
Turn on the radio and select bind mode. Wait a moment. It means bind successfully if the light on receiver keeps brighting.