There is a great booklet available from Faith Alive called "So You've Been Asked to be Mentor". I give it to all our adults who serve as Profession of Faith and leadership mentors to our youth.
Good books on mentoring include: "Mentoring Millennials" by Daniel Egeler and "Spiritual Mentoring" by Keith Anderson and Randy Reese

Do you have any resources on mentoring, specifically one on two or three, high schoolers mostly.