To get to the new Template Designer, from your Dashboard select Design. Then select Template Designer.
There are several different basic template designs that you can start with: Simple, Picture Window, Awesome Inc., Watermark, Ethereal and Travel. Under each template design there are different designs using the same basic template. For example, this blog is using the Simple template in red (which is the fourth design under Simple).
You can click on the design and see how it looks on your blog without ever changing anything on your actual blog which I think is cool. When you find a design that you like, go to the top right hand corner and click on APPLY TO BLOG. Don't hit that until you are sure that's the design you want to keep though because once you do, that's your template. Of course it's really simple to change if you just don't like it at all.
Next time I'll talk to you about the Background feature. Have a great day everyone!