When your meetup has ended:
When the meetup is over, the organiser will see a red banner a the top of their meetup (only the organiser can see this) and a green button to Complete the meetup.
Clicking the Complete the meetup button will take you to a screen which allows you to confirm the names of the people that attended the meetup.
The list of names is pre-populated using the names of the people that said they will or might attend.
There is also an option to add additional names to the list.
Completing then meetup then finalises the list of attendees and will automatically award a Socialite Badge to each attendee and a Facilitator Badge to the organiser.