If you are enrolled in a CID program then you should get the study documentation, within this are all the answers that you need.
Simply read and study it well, when you get to the exam after your training then simply use common sense, the questions were not hard and they were all related to the documents.
Previous years questions will not likely be available.
The only way you are going to fail is if you have absolutely no experience of PCB design, in which case your doing the CID too soon.