It's my first round too and I haven't personally had any phone interviews yet. There is an interview advice thread that may be helpful, though (https://forum.thegradcafe.com/topic/121366-interview-advice/). This is what @SocialPsych2018 said:
That's great info! Thank you. This is my first round, so I was just curious what to expect. I hadn't heard about the informal interviews until after submitting applications and finding this site. I haven't applied to any of the same schools, so the general questions are perfect.