Yes too easy. Only two CAN wires connected to tractor.
I suggest first you order:
2x Arduino Uno
2x CAN shields
1x 10k pot
1x switch
1x button
Build Project 3 (post 53 here) then you can test the tractor and turn wheels manually to see how it works. From there you can use AgOpen.
All you need to use AgOpen is:
1x Arduino UNO or Nano
1x CANBUS Shield
1x BNO085 or CMPS14
1x GPS receiver
EDT3, CAN 1 should be the steering bus.
Or into the AutoSteering connector