Selling better by adding Videos or Youtube links

Does anyone know how to add youtube links like this artist did to one's rendered images and screen shot area?
https://www.cgtrader.com/3d-models/animals/dinosaur/dinosaur-triceratops-robot

Hi marvimation,

In regards to your question.

On the file upload screen where you add your application files and standard images, there will be a cross at the end of the add images section.
Click this then paste the URL to whatever site your video is hosted on.

Dave