The page "Header Image" field populates the header background image.  If a header video is present this image will be the preview image while the video is loading and also serves as the fallback for mobile.

The Header Text wysiwyg field will display as an overlay on the header image.  This can be text, images, etc.

Using the field "Header Background Video (mp4/h264)" will replace the background image with a background video.  The video must be MP4/H264 formatted video and should have a ratio of 21:9 (to match your header image ratio/size).

*NOTE - This is a looping/muted background video so the video should be kept short in size/length (under 1 minute).

If a rotator is assigned to a page the images will display as slides.  The title and caption or optional and will display as an overlay.