To change the landing page structure, go to the back end of the page and click on "Page Regions" at the top. You will get an idea of the different regions that are rich in the current structure. To customize it, click Change the Region Structure.
Once your choice has been made, you can move the existing windows on the landing page to other columns in the new registry structure. Click 'Save' to apply the new structure. Also now it is possible to move panes within the structure.
On other page types, the registry structures are fixed to the right and bottom of the page. What may be is rearranging the panes in these regions.