In order to record, upload or select videos from LinkedIn, you must have the Dubb Chrome Extension.
Visit the messages section of your LinkedIn profile.
There you will notice a Dubb icon on your messages.
This allows you to record, select or upload videos directly from LinkedIn.
Once you add a video, you will be able to paste it directly into a LinkedIn message.
Once you finish adding a photo, you can simple paste the video into a message. Once you do this you will see a thumbnail graphic.