After logging in you can click on top left, and in the menu you choose 'Schedule'. If you want to book a lesson in a schedule, first check if you're on the right schedule. You can click on the arrow next to Room 1, and then you see (if your club has multiple schedules) you can choose the schedule you want to book.
You can choose a lesson that you'd like to book, you will see directly if you can book the lessen, or that you have to purchase credits with your club.
If you go back to the overview of the day, you'll see your booked lesson is green. Also, you get (if your club has set this) an email confirming your booked lesson. If you want to cancel your class, you do this by going back to the scheduled activity and click "Cancel booking."
Tags: schedule, books, mobile, iphone, android, reservation, cancel, stop