So we're not to put that button until after the event has passed?
You can push the button whenever you like
, but only those people who are marked as "Attending" will get Time Keeping entries added. Most people wait until the event has past, adjust who attended and who didn't and then press the button.
If Automatic Time Keeping for events is on, the system will add the time keeping entries as soon as the event is finished. But the automatic method relies on people marking their correct attending status and then actually attending the event. The button in question was added because people often don't keep their attending status up-to-date.