Instructional video is a kind of tutorial videos. Its goal is to help people figure out something or learn how to do something.
The instructional video explains in details and frame by frame the steps that are necessary to achieve a certain goal.
The instructional videos are now very popular, because anyone can appreciate their advantage over a simple paper instruction.
Only instructional videos can show a device or an object from all sides in natural scale. Besides, narration, subtitles, explanatory photos often accompany the instructional video.
This all helps fully to understand the given information and figure out the complicated structure of the device or a complex process.