If people people end up on the waitlist directly when they sign up it is probably because the "Approve all attendees manually" function is activated. Then everyone who registers automatically is placed on a waiting list from which you can select participants.
You can uncheck the `Approve all attendees manually` function by following these steps:
Click on `Settings`
Click on `Setup`
Uncheck the box `Approve all attendees manually`
Options for Waitlist
If you haven't got "Waitlist" checked, the event is full when the maximum number of attendees have registered for the event.
If you have "Waitlist" checked, a waiting list kicks in when the event is full. If a place becomes available it's the person who is first on the waiting list who gets a spot on the guest list.
"Approve all attendees manually" is a function that is often used at limited "VIP" events where the organizer controls who will get a place.