You can use a custom stage to have applicants watch a video or complete some type of task, and then click a link ([PORTAL_LINK] or [PORTAL_URL] merge key), when they have finished. This then automatically moves the applicant to the next stage.
For example, you could embed a video in the Applicant Portal and then instruct applicants to watch the video.
Then, you could add a "Please click here after you watch the video" link with the URL set as the [ADVANCE_URL] merge key.
The action of clicking that link will take applicants to the next stage of the workflow if you have the 'Advance by completing an action' setting enabled. If you have any further questions regarding this, please feel free to send us an email at firstname.lastname@example.org.