Do you want to trigger a workflow from a gerrit event? This kind of hook is for you.
You have to:
With this hook, you will have access to specific variables:
gerrit.change.id: ID of the changegerrit.change.url: URL of the changegerrit.change.status: Status of the changegerrit.change.branch: Destination branch of the changegerrit.ref.name: Full reference name within projectgerrit.change.ref: Git reference of the change