There is no left section. Only a middle and right. However, none of that really matters as you can design the elements to be wherever you want them. What you need to remember is that a page consists of:

header.tpl
(some body).tpl
right.tpl (on some pages unless you include it on all)
footer.tpl

But, just because they are separate files doesn't mean that you have to use them like that.

For example, you could make "header.tpl" everything up to your body tag, "footer.tpl" your footer, eliminate the "right.tpl" altogether, and just use the "some body" portion as your entire site. Your choice really.

It sounds a bit like you need an HTML/CSS tutorial? Are you understanding what I'm saying or do I need to explain something differently?