Donald Trump's campaign staff is ignorant on many important issues. His spokeswoman has made many incorrect statements during the campaign. Furthermore, Trump's staff has been unable to school him on important foreign policy issues. Trump should surround himself with experts that can provide solid advice for his campaign. He should also have people that can better articulate his message, and not get so many things wrong.
No, his staff is not ignorant on the issues. If Donald Trump's spokeswoman Katrina Pierson says (incorrectly) that it was Obama who "went into Afghanistan," it was probably just a mistake. People make mistakes all the time and they should not be harshly reprimanded or scolded both in the media and in real life for something like that.
These people know that if you sling enough mud at a person, some of it sticks, so they can invent stories or give out incorrect information which they later retract, but the damage is already done. People hear and remember the bad things but don't necessarily listen to remember any apology or correction made.
I would not say that Trump's staff are in any way ignorant of the true facts behind the sound bites that they espouse, rather that they are savvy enough to put a desired spin on the information and are not above speaking out falsely in order to strength their own position.