You'll get an invitation to opt in to every Saving Session. They'll be sent with as much notice as possible – ideally the day before.
Shortly before the Session begins, you'll receive a reminder.
Within a few days of the Session, you'll receive your results.
All these notifications will come via email, and if you have the Octopus app, via push notification too. Here's how to download the app and make sure you've enabled notifications.