How to add Code within Template Background:
1) Under "Site" Menu on Left hand side of Builder
2) Select "Design"
3) Click on the Gear symbol on the right bottom corner of the Builder
4) Select "Customize"
5)Under "Template" Select "Background"
Here you can add code and once completed activate your changes at the bottom.
We recommend consulting a code expert before making changes to your site's code and backing up your site before you make these changes.