Care Plan Confusion

Hello. I am currently working on my first care plan. I originally thought that I had a basic understanding of how to create my diagnoses. Our format for school though is super weird though. It is separated into three columns: First column is for NANDA diagnosis. I understand that. Second is for supporting Pt data (relevant symptoms/defining characteristics/specific data gathered from assessment), instructor told us to put the related to part here (this seems to be the AEB part to me). The last column is for Dynamics (defining characteristics from med-surge book; supports this as a problem). We were told to look for signs and symptoms from another source that supports out diagnosis. How do we even do that. I have been confused since Thursday and I tried to get clarification from our instructor, but it was hectic during post conference due to the next group coming in. I was under the impression that our diagnosis was to be assessment driven. What does the patient's symptoms tell us, that leads to the diagnosis. I don't understand how to use another source to support our diagnosis? If anyone has any ideas and would like to share how to attack this I would greatly appreciate it. Thanks.