You would need to get the 332C display and then add the trolling motor transducer (unless you have universal sonar, then you would need the MKR-US-5 sonar cable instead of the ducer). The trolling motor ducer is PDT-WBL.
You don’t need any special cables. You can wire the two together using the NMEA 0183 port. There are a few guys on here that have done it and can help you if you get stuck I’m sure. I have the wire diagram I can get for you if you go that route. You can order any of this though Jolly Ann Marine or local places like Cabelas, Reeds, Thorne Bros, Gander, and Bass Pro should all have it as well.