Please take a moment and update your account profile. If you have an updated account profile with basic information on why you are on Air Warriors it will help other people respond to your posts. How do you update your profile you ask?
It completely depends on how comfortable you are in the water. The instructor will explain what you need to do, demonstrate it, then allow you to practice. If you are a strong/experienced/comfortable swimmer, you should not have issues. If you don't pass first time, not really a problem. Keep practicing!