The Age Field calculates and stores the age of the record in a field contrarily to our older Age Field which is only an indicator that displays the age. This means that you can then see the age in your lookups and reports (although you'll need to update the field, see the bottom of this topic).
2 fields to be selected
1. When you add Age Field 2 to the layout, you're first prompted to select the field where you want the age to be stored.
2. Once you close the Select field window, right-click the control and select DOB Field to select the date field that will be the reference for calculating the age.
The age is calculated automatically when you display the record. If you wish to update a lookup of records, right-click the field and select Update current lookup. You'll notice the Update command that is really usefull only after you just changed the related date field.