Here is an example Spektrum RX Satellite setup guide. I'll show you how to bind it with your transmitter using betaflight version 3.1.6 and newer. I'll be using an OmnibusF4 in my example.
On the OMNIBUSF4, the UART1 RX pin is available for use on 3 different headers, only one of which can be used at any given time:
Configure the flight controller for your receiver by opening the BetaFlight Configurator and on the ports page, set UART1 to Serial RX and click save. Switch to the configuration tab and in the Receiver section, set the mode to SerialRX and provider to either:
In the CLI run:
set spektrum_sat_bind = 9 set spektrum_sat_bind_autorst = 0 save
Wait for the board to reboot, then remove all power from the board (unplug the USB), wait a moment then and plug the in the USB cable.
The bind light on the receiver should be flashing.
Turn on your transmitter in bind mode.
The flashing light on the receiver should now be solid.
Turn of your transmitter.
Finally take the receiver out of bind mode by running the following in the CLI:
set spektrum_sat_bind = 0 save