Upload video instead of image

1. Site > Control Panel > icon Product list

2. In column Media click the link (number):

3. Click icon New:

4. Fill in the form:

File type: select Additional Image;
File Title (what the Customer sees): if your video name must be else than file title, you can write it;
File URL (optional): write the youtube url link:

5. Save changes and in the product page you will see the video. In administrator panel you will see the word Youtube in image position.