As soon as you finished the detail registration, you need to finalize you profile on the event website - else recruiters won't be able to see you.
2-3 week before event start, recruiters will start the screening process. From there on, you can be invited to company dating. So please have an eye on your inbox within the event platform.
You can accept, decline an appointment and propose a new time for the appointment.
Only recruiters can invite you to meetings, you cannot reach out directly to recruiters.