Many virtual training sessions require a working camera that is on throughout the entire session and the host may not admit you without it. Please check your confirmation email for session requirements.
Users with smartphones sometimes solve this by downloading the Zoom app to their phones. The Zoom guide here will walk you through the steps needed to join from any device. If you do not have an available smartphone and your employer requires you to complete a training, you will want to reach out to your supervisor for guidance.