The interview questions are all about the competencies. You must have an example ready for each. The interviewers allowed me to have my notes to refer to - as long as I was not directly reading out of the notes. I had prepared answers for the "Leading and Communicating" competency, and mainly focused giving an example on leadership. However, during the interview I found that they wanted to know more about how I communicated. So do prepare answers for both parts of the competency. In addition, they also may ask how you supported someone else in making a decision. So have an answer prepared for this as well.