Typically they use an outside source to bring in contractors, that are already vested by a third-party company. So before you get brought on, they will make sure the third party has done its diligence in making sure the employee coming for the first interview has been qualified to even sit. The standard process from HR in terms of interview setup and processing of paperwork. Ask a lot of questions around scenarios, A user does this what do you have them try next? Then once finished with standard level 1 scenarios. the person interviewing you, usually your supervisor or a team lead will ask questions about employment status and how they effectively used their skill set to pinpoint your strengths and weaknesses in all IT areas. Questions on technical stuff increase as the hiring manager wants to know what level you are at and what you can process quickly under some stress of the interview. Tell the truth, you're not expected to know everything.