Right Sidebar: This sidebar area is displayed on the right side of the homepage, blog page, archive pages, single blog pages, 404 page, search page, and other pages.
Left Sidebar: This sidebar area is displayed on the left side of the homepage, blog page, archive pages, single blog pages, 404 page, search page, and other pages.
Full-Width Widgets Area: This sidebar is displayed at full width on the front page, and all the widgets you add here are displayed in full width.
Primary Widgets Area: This sidebar is displayed middle of frontpage section. You can add widgets that you want to display beside the secondary widget.
Secondary Widgets Area: This sidebar is also displayed middle of frontpage section. You can add widgets that you want to display beside the Primary widget.
Above Footer Widgets Area: This sidebar is displayed just above the footer section of frontpage section.
If you want to add a widget area in the footer then you must add widgets in Footer Widget 1, Footer Widget 2, Footer Widget 3, and Footer Widget 4.