User watches a Vimeo video trigger lets your users to complete an automation by simply watching a video letting you run any action of your choice like send an email to the user, enroll user in a course or included add an affiliate referral.
When you add a new trigger, you can find the user watches a Vimeo video trigger under the Vimeo integration.
This trigger configuration looks like this:

The unique setting is the number of times the user needs to watch the video to mark this trigger as completed.
Embedding the video
User watches a Vimeo video trigger gives you the [automatorwp_vimeo] shortcode configured with the trigger attribute that you need.
[automatorwp_vimeo] shortcode accepts a set of attributes that you can use to personalize different parts of the video like the video URL or the player width and height.
Automations samples
You can check the automations samples page where you can see some samples of the possibilities of this add-on.