Configure at Admin → Extensions → Template Manager → rt_gantry, then go to Layouts tab and set the varying Mainbody/Sidebar layout possibilities.
Here, you can change both the grid size of the Mainbody/Sidebar position, but also the location of the sidebars. You can place the sidebars at varying combinations to the left, right or both or the Mainbody.
There are times when you just don't want to have your modules taking up all the room in a horizontal row no matter what the layout. For example you might want to have a module on the left and a module on the right, with nothing in the middle.
This is made easy with Gantry with the Force Positions parameter for each layout, allowing you to set the count to a specific row number, such as 4, even if 4 modules are not published for that row.
Features are specific elements of functionality, that are incredibly flexible and can be used to perform any kind of logic you would need. They are injected into a position when enabled, and are stacked vertically; inclusive of: Date, Font Sizer, Login Panel and more.
Configure at Admin → Extensions → Template Manager → rt_graffito, then go to Layouts to set the grid widths and allocated positions.
By default, each grid is given an equal distribution, but this can be modified to a custom distribution between modules, such as 3/4/5 instead of 4/4/4. These options are available for when 2-6 modules are present.
If no modules are published to a position, the entire area or row will not appear or collapse.