As an advisor/facilitator, you will be responsible for:
scheduling the meeting
choosing the book AND/OR preparing discussion questions
comfortable, safe meeting place
It's probably a good idea for you as the facilitator to choose the first book you read (if you're using the Read and Discuss model). You might even want to choose the first two titles. Then give your students the responsibility of choosing the next few titles. The book club is their club and they should have a major say in what they read. Often, if someone (teacher/parent) tells a young person they have to read a specific title, they run as fast as they can AWAY from that title.