In the Media Pool click category 
Trigger, right-click the corresponding trigger and select Add conditions. Under Scheduler conditions right-click some free space in the list and choose the required function:
These functions require the Show Control Module. See Licenses and functions.
For time-related conditions you can choose between selecting a simple point of time and a more differentiated schedule.
In the Media Pool click category Trigger, right-click the corresponding trigger and select Add conditions. Under Scheduler conditions right-click some free space in the list and choose the required function:
New date for certain points of time or time ranges
New date pattern for more complex applications (e.g. referring to a particular day of the week)
If you want to modify existing conditions, right-click the trigger and select Properties.
All conditions of a trigger are connected by AND operations. The trigger actions are only performed when all conditions are met. If you require triggers linked up by OR operations, you can create a number of copies of the same trigger and assign different conditions.
In order to enable time control for trigger based on certain conditions, click on 
Enable trigger scheduler to press the button. See also Enabling the trigger scheduler.
Here you can enter a date and a time as a condition, which are both connected by an AND operation. The condition is only met, when both parameters apply.
Example: 22.09.2003, 14:40:00 ...this condition is only met for one second.
If you select >= additionally, which means "larger than", the condition is met starting from the specified point of time.
Examples:
22.09.2003, >= 15:00:00 ...this condition is met on 22.09.2003 from 15.00 to 24.00.
>= 22.09.2003, >= 11:00:00 ...this condition is met from 11.00 to 24.00 on 22.09.2003 and any other day following it.
>= 22.09.2003, 08:30:00 ...this condition is met at 8:30 on 22.09.2003 and any other day following it.
Enter any names and remarks in fields Name and Comment. They are displayed in the Media Pool in the corresponding column.
...Move on to Creating a trigger
This dialog allows you to specify certain schedules considering a variety of criteria. Please bear in mind that all parameters in this dialog are linked up by AND operations. This has far-reaching consequences.
Under General you can specify a period of time the trigger function is to be valid. Enter any names and remarks in fields Name and Comment. They are displayed in the Media Pool in the corresponding column.
The parameters entered for Months, Weekdays and Days in month are linked up by AND operations. If all the checkmarks are ticked, all these conditions are always met. Unchecking certain check boxes means that certain restrictions are applied. Use buttons All or None to select or deselect all checkboxes.
Also the parameters under Times are linked up by AND operations (all of them, vertically and horizontally!). Under Hours, Minutes and Seconds, you can select various operators by ticking their check boxes and defining time ranges. However, make sure that the combinations make sense, e.g. Minutes >= 15 and <=10 is a condition that can never be met.
The parameters under Times at the very right are used for specifying an interval, which can additionally be provided with an offset. If you enter Every 5 minutes, as shown below, this condition is met at 0:05, 0:10, 0:15, 0:20, etc. until 24:00.
However, if you enter Every 5 minutes and an Offset of + 2 minutes, this condition is met at 0:07, 0:12, 0:17, 0:22, etc. until 23:57, 0:02 and so on.
Further examples of time schedules:
Here, a time range, an interval and an offset have been entered. These conditions are met at 9:15, 9:45 .... 16:15, 16:45.
Considering these conditions, a trigger function would be performed every 20 minutes between 14.00 and 18.00. The parameter Minute >= 15 and <= 45 restricts the time range once again. The resulting execution times are as follows: 14:20, 14:40, 15:20, 15:40 ... 17:20, 17: 40.
...Move on to Creating a trigger