Reading through all the rules and regulations should answer many of your questions. You’ll want to check the provincial syllabus and local addenda for all your class information, and write down the number and title for each class you wish to enter. Make sure you have the complete repertoire information including title (key, opus, no., movements if applicable) and composer and an accurate timing of your selection.
These pdf documents will help you through the registration process. The worksheet shows what the registration site looks like (teachers, you could even fill this out for your students) and the instructions provide details of all steps to successfully register.