In practice session you have assignment, these assignment are given to you by your mentor. You both get an assignment, you are going to help your partner and your partner is going to help you in completing this assignment. Once the assignment is over, you can talk about your past assignment or anything. Just keep the conversation gentle. Any type of healthy discussion you can do. You can talk about your hobbies, your interest, how to introduce yourself and any type of regular conversation. This will make you feel better and build confidence.