How to add Meta tags to pages:

1) Under "Site" menu on left side of builder

2) Select "Pages"

3) Double click on the page/background you wish to add meta tag to

4) Click "Meta" tab on the left side 

5) Click the "+" icon on the bottom left of builder

6) Here you can fill in the "Type" "Name" and "Value"

Make sure to publish your changes.