Trigger Events allow you to auto-generate a task when one or more Trigger Events occur. You can review existing Trigger Events for Task Types by hovering over the Tasks module and selecting Manage Task Types. You can then select the Task Type you wish to view.
For instance, the Receive Non-Final Office Action Task Type has the following Triggers:

Note that you may add new or additional Trigger Events to a Task Type by clicking the Add button under Trigger Events:

You can also click the Add button within a Trigger Event to add a trigger to any condition without having to delete triggers after it and re-add them.

There are numerous ways to use Trigger Events in AppColl. Below are some examples:
Auto Generate Calendar Entries When Tasks with External Deadlines are Created
Generate Tasks from Emails Received into AppColl
Send Client Reporting Emails when Tasks with External Deadlines are Created
Create Extendable Deadlines for Tasks
Add Foreign Annuity Payment Tasks