Want to project on Arduino due

Hello! According to your steps, I have successfully projected on Arduino UNO. Now I want to project it on Arduino due, but it always shows that "portb" is not defined in this scope! I have been checking for a long time and I don't know how to modify it. I'm still a rookie. Please help me try it! Due to geographical reasons, you should rest, sorry to disturb, very urgent!

Your Chinese friend Li