Connect with at least one of your teachers, preferably one teaching a course in your current curriculum, who inspires you to learn and begin collaborating. (If it can help get started, consider collaborating on the design of an ecosystem studies research project or even a seminar session you can present to your fellow-students later this school year.)
The crucial purposes an academic advisor serves include inspiring you to learn in a scholarly environment where you can take full advantage of the benefits provided through disciplined practice in the arts and sciences. Essentially, you need to establish a working relationship with a teacher at your school; an advisor who can guide and hopefully support you in preparing, delivering and evaluating the academic presentation components of your YESSS contest entry.
You and your advisor will be responsible for assigning a grade to your academic work. If you're not going to aim for a grade of "A" or "best-in-class", then you may not want to participate in YESSS contests. Even though grading academic work is certainly not what learning's all about, getting an "A" can be fun and it does help to distinguish scholars from those who are less academically-inclined. (YESSS does exist for scholars of a certain kind.)
YESSS encourages and acknowledges academic excellence; whether a contestant's entry is part of an accredited course of study or an independent study project with or without academic credit.