The Timer Start Event (Trigger property set to 'Timer') allows setting a specific date and time to start the process instance or even a cycle of executions of new process instances.
This event indicates a specific date and time for the process instance to start, or a cycle for recurring executions. You can configure those date and times at design time or at runtime.
Note: In order to see the Timer Events reflected in your inbox, you must run a program that checks and executes these events. See Timer Control for more information.
Timer Intermediate Event in BPD
Timer Control