@niki,
At first glance, I am really concerned about this situation. I don’t know where you work or the size of the organization or location, but to my mind it is dangerous if not criminal for an organization to give someone absolutely no training or guidelines about how to conduct an interview and more importantly, what questions may or may not be asked in an interview.
At minimum, you should be told what not to ask, and how to phrase the touchy questions in a way that you stay within the law and still elicit the information that you need in order to make a decision.
If there is an HR department where you work, someone is sleeping on the job big time.
Look I hope I am not blowing this out of proportion but this can be a tricky situation if mis-handled,
You really ought to talk to HR and get some idea about what you should be doing in an interview.
That being said, the purpose of an interview is to obtain information about the candidate and give him or her information about the position and about the employer.
You have received some good advice on Fluther so far, the trick is to make yourself comfortable in the interview and to put the interviewee also at ease. Don’t try to ask tricky questions or try to trip up the candidate, just be yourself and ask those questions that are necessary to discover what you need to know about the candidate.
It is not a problem for you to have a list of questions that you can follow., you don’t want to inadvertently omit something critical. You should take notes, and if something is unclear, ask the candidate to clarify the response.
There is a lot to add here but you have gotten the basics.
SRM