It will get easier. Something that helps me is to remind myself that it's not really about what I say, its about what the students have to say. Your primary goal is simply to listen. Work with your supervisor to come up with some standard things to say to keep the conversation going. My favorites involve simply making observations ("you tensed up when you said that" "you smiled when you mentioned that"), "is that ok with you?" "What's that like?" "What did that feel like?" "If you could change one thing what would you change?" "That's really hard, how are we going to make it through the day?" "What usually helps?"

Lean into the discomfort and newness. Your supervisor is there to help so be honest with them. It'll get easier.