The OpenCart default store provides the following page layouts:
If you haven't done so already, you should take some time to browse the store front. To become familiar with layouts available in OpenCart, you should visit the different page types of your store front. The Manufacturer page layout has a different type of layout than the Checkout page, which has a different page layout than the Information page, and so on. It's good to see how these layouts arrange themselves, to discover how positioning a module from the Extensions section will affect the overall look of the page.
Creating a layout page from scratch takes some knowledge of web design and development. Once a layout page has been created, you should upload the files with an FTP client.
The location of the layout pages in the default theme is visible under /catalog/view/theme/default/template/ in the OpenCart directory. You can see that all the page layouts from the default are included as folders above. To add a new layout page, you would need to upload the files under a new layout folder.
After the new layout page is uploaded to the location above, it can added to the store by clicking the "Insert" button under System > Design > Layout. The new layout will require a layout name, the store the layout will be added to, and a route. The route is the folder name that the layout files are included in. OpenCart knows to search for the folder under /catalog/view/theme/default/template/ in the store directory, so only the folder name is required.
Clicking "Add Route", then "Save" will make the new layout available in the store. See Modules for more information on how to add a module to a specific layout page.