Interview nerves, what actually helps? - any advice?

I have an interview on Tuesday and my stomach is in knots. I worked as a procurement assistant before this. I want to come across as confident and honest. Any questions to ask at the end?

Thanks for writing this out. I went through something close to it 7 months ago, and it settled down once I kept a simple log of every call and form.

Prepare three stories with a clear beginning, action and result, and adapt them to the questions.