Interviews can be daunting, whether you are the one asking the questions or the one answering. Thinking of an interview as a conversation can be helpful. Journalists interview people all the time, as do historians for oral history projects. You can utilize their techniques for your interview about an ancient philosopher!
Below are some resources that advise on how to come up with good questions, how to keep the conversation going, and much more.
While not necessary for a class project, if you are going to broadcast your podcast to a wider audience then you will want to make sure that you have the permission of anyone whose voice will be used. Below are some links to release forms templates you can tailor to your own project.