what questions do they ask you in the interview?
99.9% of us went in not knowing what questions to expect, so in all fairness you should too. Just prepare yourself for general interview questions and some regarding your experience.
You have about 15-20 minutes to sell yourself, bring copies of all supporting documents for any licenses or certificates you may have. Be 100% you, don't try to answer in other ways that are not you, because interviewers can see through that. Wear slacks/khakis and a nice button up, don't need a suit.