To add a background video on Squarespace, just follow these simple steps.
#1. Edit the Squarespace page where you want to add a background video > EDIT SECTION
#2. At Background, click on the plus icon (+) to add background video
#3. Besides uploading a file, you can add the YouTube or Vimeo video link to the background
#4. After uploading the video, click SAVE on the left of the screen
#5. Result