A trigger describes when to start a recipe. Each recipe must one trigger. The trigger would be an event that the recipe will be listening for when you start the recipe. At the end of a polling cycle, the recipe will check in the app to see if there is any record that meets the specified trigger.
For this example, This recipe will fire whenever an opportunity has been created or updated in Salesforce.
Since allows your recipe to go back in time to pick up history objects that meets the trigger condition up until the present time and move on from there.
You are either able to choose from the dropdown fields,
Or, you can click on the toggle and choose a specified date and time.