To get the latest or earliest date, date and time, or time of day, you use the Maximum and Minimum functions.
For example, to get the date of the most recent event, you could write
the most recent event date = the latest of the date of the annual Arts Festival and the date of the annual Music Festival
If the date of the annual Arts Festival was 2001-05-05 and the date of the annual Music Festival was 2001-03-15, then the most recent event date is 2001-05-05.
To get the earliest completion time of two teams, you could write:
the earliest completion time = Minimum(the completion time of Team A, the completion time of Team B)
If the completion time of Team A is 16:45:02, and the completion time of Team B is 16:14:18, then the earliest completion time is 16:14:18.