The daily trigger will start builds at exact times and continually do it at the specified interval until you either delete or disable the trigger.
The time can be typed in or specified by using the time picker which can be displayed by clicking the clock icon next to the input field for the Time.
After specifying a time, you can select when you want it to repeat. The options are Every Day, Every so many days (you specify the number of days in the input field that gets displayed after selecting this option), Week days only and Weekend days only.