A shop like Magento has many Ideas and functions, which is great. A custom template to even better.
As a prerequisite, you should also definitely the Designer’s Guide have read 3-4 times. Should have been raised still more questions here – To whom then – as in my case.
No one will seriously want to create a new Magento theme without resorting to an existing theme. The basic theme (default) consists of nearly 500 files and folders. Add to that the CSS and image files.
Taking the basic theme, as a starting point layout changes are quite simple. Under no circumstances should you work in the original files. Otherwise, the next update of the theme all modifications are gone. (Secondary) accepted our new theme is to say My Theme, so you put in the directories app / design / frontend / default / and skin / frontend / default / each of the new subdirectory My Theme on.
Change the files you want to copy from now default to My_Theme. The path for the file in the default branch reveals Magento when backend under System / Configuration / Advanced / Developer Tools / debug mode enabled (Set Current Config field on the website!).
Then, to see the changes in the shop, you need to tell Magento yet to use the new theme. For this, one is in System / Configuration / General / design in themes / default the new theme My_Theme one.
Now, if you clear the cache, or has it turned off directly into the cache management, in the store, the changes appear. This shows the strength of the template system of Magento. Instead of changing the templates directly to work in a separate area. Magento looks when rendering a page always first in the folder My_Theme. If there is not the required element is removed from the default.
Up to this point, you could see the information also in the Designer’s Guide found. I then tried the Modern Theme to take as a basis for your own theme. Here, you have to know that this theme is derived only by default. Therefore, it cannot work as Standalone theme without default. If you try, some sites do not work anymore. For example, the comment page to a product.
Therefore, you have a hierarchy in the form of default -> state -> Set up My Theme. This too is not a problem in Magento.
Magento will initially always the blocks from My_Theme. Then comes the turn of modern and last default.