when it ask for the unit ( tractor, reefer, etc..) select whatever, i always select tractor. sometimes it will ask the unit number, just make one up 1234. it will ask if you want cash back, it will ask if you want any other products from inside. then it will ask about a control number. It will ask about DEF fluid at some point also. if you are getting DEF, once you get through all the prompts just pick weather you want to do DEF or diesel first by lifting that nozzle, after you finish it will prompt you to start the next fluid.
This is a good video to help https://youtu.be/Xc2UwKjEJz4