We are using ContestCompass.net for submissions this year - please go to ContestCompass.net to register for your account using a join code that your teacher has created for your class!
Here is a guide from Contest Compass explaining how submitting your entry to the platform works: https://contestcompass.net/page/how-to-submit-an-entry-to-a-contest
If you need help of any kind, please use the Contest Compass support ticket system - you can direct your question either to the Caring For The Kenai staff, or to the platform, depending on what you need. You can find that system here and use it when logged in: https://contestcompass.net/support