The best way to “kick off” the school year is by introducing students to the idea of public speaking. Some will be very confident; others will be very intimidated. Using an “icebreaker” to get students to not only do a short oral presentation, but also get to know the other members of the class, is a good idea, and several such ideas are included in the CLASSROOM link.
You will also want to distribute and explain your classroom syllabus, rules, and a basic synopsis of not only what the class will involve, but the idea of debate tournaments and what they entail. Several examples of syllabi and student paperwork packets are in the COACHING link.