Videos should be added as the first line of the product long description.  Product long description will need to be sent as html.

It should look something like below:

<iframe width="560" height="315" src="" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>
Note the video URL as src=""

When you go to youtube/dropbox/google drive videos, there is a embed option, which gives the embed HTML.