How to Add Link preview to app store connect?

It is my first tile that I try to send my app to app store review. but i have received this message from apple team "Provide a link to the video in the App Review Information section of your app’s page in App Store Connect and reply to this message. You can use a screen recorder to capture footage of your app in use. Note that if your app can only be reviewed with a demo video, you’ll need to provide an updated demo video for every app submission." it is clear that i need to add a video preview of my app. But i still confident how to provide this link? And how to add this video i see in app store connect the field attachment it is the corresponding field?enter image description here