Setting date and time allows you to specify additional filter criteria on properties that store a date and time.
Calendar - Allows you to select a specific date.
Today - Selects today's date. If you want to set a date that is a specific period from today, select Today plus (+) or minus (-) number of Days, Weeks, or Months.
Ignore non-working days - Allows you to ignore non-working days in the default calendar for the site when calculating the duration. The default calendar is selected using the system options. For more information on the system options, see Configure the system options.