They are expecting where it shows on the right for receiver input but also note there says any UART can support being the "receiver", the important thing basically is to select the corresponding "serial RX" toggle on the ports tab in betaflight, so if you use R1/T1 use Serial 1 etc., then check in the receivers tab to see if the receiver is sending data to the FC. Once the transmitter and receiver are bound and protocol set from transmitter to use s.bus I think it should work okay?