Hello there! Good luck on your interview. I know how hard it gets to feel overwhelmed like that
For the interview, focus on your personal statement (do you have a personal statement? The one that you wrote in it about your life). Focus on your life's events that led to you seeking asylum. Focus on your country conditions, but also on YOUR story. What happened to you? Why do you feel scared to go back? What may happen if you go back? What do you identify as (religion, political opinion, gender... etc.)
It is 2 hours because officer wants to make sure your story is REAL. They want to know that YOU are SCARED to go back for strong reasons