Registration
A date runs from four registrations. Until it is confirmed, your registration is non-binding and free. You will know at least ten days in advance whether the date goes ahead. The invoice comes only after that.
The overview with agenda and prerequisites is on the format pages.
The most useful sentence in the whole form. The more concrete, the more likely your case ends up in the day.
No payment in this step. An invoice only comes once the date is confirmed.