Cliche but I had an ac yesterday and before I started every task, I took 3 deep breaths. Before I started my strengths based interview with a partner, I did this and it really relaxed me. in your interview, if needed, don’t be afraid to ask them to repeat a question or to take a minute to think about your answer.
Try to relax, be yourself and do your best! Follow all instructions of any tasks you are set. Take a watch and manage your time as best as you can. Best of luck!!