Date fields can be regarded as a subtype of text fields. The date
can be entered manually or selected from the pop-up calendar.
Dates can be entered without a date separator, but are shown and saved with
the date separator set in Windows Regional Settings.
Open the calendar by clicking the down-pointing arrow.
Select a date by left-clicking it. Alternatively, use the cursor keys to
move around and 
to
confirm the selection. Click the Today button to quickly set today's
date.
On the left you can see current week of year (for informative purposes).
Use
and
to move back and forth between months and years.
The month can also be selected by left-clicking the month name in the calendar
header and selecting it from a list of adjacent months.
The same can be done when setting year. Left-click the currently selected
year and a lookup appears where you can select it.