I am very new to WordPress, so please excuse what I’m sure is a silly question, but how do I apply a theme that is from a website other than WordPress? For example, if I want to use this theme for my site: http://studio.st/i-feel-dirty/
and I download the file, what do I do with all those files and how do I apply this theme to my site?
atthe404’s answer was the succinct one. This is the pithy: The only themes you have available for you to use on your WordPress.com blog are the ones you will find under Presentation in your Dashboard. That’s it. Some of these allow you to use your own header image and, if you buy the upgrade, you can edit the CSS as well.
As very new to WordPress you might want to spend some time poking around the FAQs. I found them very helpful when I was just starting out here. Have fun.