Create a trigger with the “Add trigger” on the first tab of the events settings page. Creating the trigger involves two steps, just like creating a view: first you specify the basic properties of the trigger, including the event type to run on, the action to perform in response to that event type, and possibly the table or channel name. Some actions, for instance send an email, are only available on event types that are associated with tables. You should also specify a name for this trigger. Once these have been chosen and you click save, you will be taken to the configuration that is specific to the chosen action (just like when you create a view, you are taken to the configuration specific to the chosen view template).
Once the trigger has been created, in the list of triggers you can edit the basic properties (Edit), change the action configuration (Configure), or perform a test run. The latter will capture and show to you on completion console output which you can use for debugging.