Before setting up optional CAT control I would recommend configuring everything else without it (RIG=NONE, PTT=RTS) and making sure you can get some QSOs.
When it comes to CAT settings, the baud rate must match between the software (WSJT-X) and the setting in the transceiver. From the manual it appears to be under menu #57. 9600 baud is known to work well based on several reports. Other speeds should be good too.
Other settings: Data Bits = Eight, Stop Bits = One, Handshake: None, DTR: blank, RTS: blank, PTT: RTS, Port: [select one from Digirig], Mode: None, Split: None