Most likely you have some sort of script that you are required to read to inform clients of their rights, as well as a set list of questions to ask in order to determine their eligibility. If you're not familiar with these questions and this is your first interview for the job, look at the job description on the county website. You should be able to find more information regarding the specifics of the position that will help you to familiarize yourself with the types of questions you may need to ask. Since you're looking to determine their eligibility, you will need to know facts regarding their income, work status and living situation. What are some other important pieces of information you think are important?