How can I create a custom post template?

I created a file in the them folder with a .php extension and put my default html and .php code in it.

When I view a new post that is set to use the post template I created (by selecting it using the Custom Post Template plug-in), all I see is a blank white page with my default html. Nothing else show like header, footer, side bars etc.

What do I do the fix this?

Thanks. Glenn

You should start with a copy of index.php. Atahualpa needs much of that code to work properly.