How do I add sub ‘categories’?

My blog is http://www.badlandscaping.com
And I am using WP 2.1. And so far it has been a joy to use, full of surprises- most times that I need to do something I discover the feature already built in. Nice. But the underlying code remains a mystery novel and I’m only about 1/3 of the way figuring out whodunnit.

The right side of my blog has ‘Pages, Archives, Categories’. This is good.

But I am preparing a long list of articles called Reviews, and I would like to know how to do these two things, so I can decide which one works best for me:

1. Add another element at the same level as ‘Pages, Archives, Categories’, called ‘Reviews’, and

2. How to make ‘sub-pages’ in the Pages element, so I would have Reviews, then under it and indented I would have review 1, review 2, etc.

All I really need is some insight into how these elements are constructed. I’ve looked through the code, but it’s not evident [to me] how to make this happen.

Thanks!

Michael