Creating the trigger from your Zendesk settings
This step will create a trigger that will select which tickets to add the automatic pre-translation tag to. Go to Settings - Triggers - Add Trigger:
Editing the Automatically Unbabel trigger
After you accomplish the last step, find and edit the Automatically Unbabel trigger so that it is actioned when a trigger has your selected tag, and hasn't been translated yet (does not contain the unbabeled tag). Save any changes.