EasyVideo Product Videos app functionality is closely connected with your theme HTML structure, so we did our best to test it on different themes and make sure app will work without any manual configuration. But there's always a chance that your theme have some unique elements that will require a bit custom setup - DOM selector allow us to point your main product image if app failed to find it automatically.
If you're not sure what's DOM and app is not working by default, please grant our support team access to your Store Admin so we may check and configure app properly with your theme. You may send invitation to support@nexusmedia-ua.com. Please also send us an email to that address explaining your problem.