Open an Instagram Video post & click the ' ' or ' ' icon which is right side the post.
Now click on the Share Link... option.
Just Copy Link URL with simple click.
Now paste that copied url into the input field (downloader).
Press download button which is right side of the input field.
After the process, you will see two option one is the video preview and second downlaod button
Both options work similarly as Right-Click on video or download button and than "Save Video As..