Setting intervals of minutes
By default, the time picker displays minutes from 0 through 59. To restrict the time selections available to users, you can configure your application to display intervals of minutes on time controls, instead.
In the layout of the form that you are editing Adding a DateTime control to a layout
On the Presentation tab of the Properties
panel, select the Allow time to be displayed in the interval of
minutes option and click the corresponding number of minutes: 5, 10, 15, 20,
or 30.