Adding A Video To A Plugin

You will need to take the original file and upload it to a website to be hosted there (This will be under the same place as you would upload a new image for use on your website).

If your plan is just to use this as a background video, I would encourage you to have your client trim the video down to around 30 seconds to make the file size smaller for easier uploading.

From there, you will want to go into the media section of your website and grab the file URL.