A tutor answers from two places: the instructions you wrote in its prompt, and any documents you uploaded to its knowledge base.
The prompt
The prompt is the instruction set: who the tutor is for, what it should do, and what it should not give away. It is the first thing to change if a tutor is behaving oddly.
The knowledge base
Documents you upload under Knowledge base give the tutor your own material to answer from. Turn on Knowledge base citations and each answer shows which document it drew on and the passage it used.
If you expected an answer to come from your documents and it carries no citation, the tutor answered from general knowledge. That usually means the document did not cover the question.