You are using the imu.ino:
ArduinoModules/UDP/IMU_UDP_v5
Boards/ArduinoModules/UDP/IMU_UDP_v5 at main · AgHardware/Boards · GitHub
for usb:
ArduinoModules/USB/IMU_USB_v5
Boards/ArduinoModules/USB/IMU_USB_v5 at main · AgHardware/Boards · GitHub
Edit:
Wiring see 5, 6:
Wiring diagrams - Operations/Getting Started / How to - AgOpenGPS