Online Check-in can be used to check members and prospects into events as well as to track general attendance. The left side of Online Check-in will display all upcoming events with their scheduled members.
Selecting an event will expand the view and allow you to check members in, mark them absent, or cancel them from the event entirely. This will work exactly the way it works in the My Scheduler Check-in View.
If you are using the Public Calendar feature (see these articles for more information), whenever a member is marked absent for an event, whether Free absence or Paid, the member will receive an email with a link to your Public Calendar, allowing them to sign up for a new event right away.