Set up your video background to play on a loop.
To change the loop setting on your video background:
Go to the relevant page in your Editor.
Click Site Design on the left side of the Editor.
Hover over Page Background and click Customize.
Click Settings on the video background preview.
Click the Play in a loop toggle to enable or disable looping:
Enabled: The video background plays on repeat.
Disabled: The video background plays once on loading.