Configure at Admin → Extensions → Template Manager → rt_graffito, then go to Layouts to set the grid widths and allocated positions.
Injected Gantry Features
In the Gantry framework we use the term Feature to mean a specific bit of functionality. Features are flexible enough that they can be used to perform almost any kind of logic you would need.
There are Features that are injected into a position when enabled, and are stacked vertically; which includes: Social Buttons, Date, Font Sizer, Login Panel, Popup Module, Branding, Copyright, To-Top Scroller, System Messages, Reset Settings, and Google Analytics.
Configure at Admin → Extensions → Template Manager → rt_graffito, then go to Layouts tab and set the varying Mainbody/Sidebar layout possibilities.
Note: If no modules are assigned to the Sidebar positions, the Mainbody will become full width.