If you want to set things up manually, download da from GitHub. The first thing you want to do is copy the da directory and change the name to something else (like, say, megatherium-is-awesome), and then you'll need to do a five-step find and replace on the name in all the templates.

Search for 'da' (inside single quotations) to capture the text domain.
Search for da_ to capture all the function names.
Search for Text Domain: da in style.css.
Search for  da (with a space before it) to capture DocBlocks.
Search for da- to capture prefixed handles.
OR

Search for: 'da' and replace with: 'megatherium-is-awesome'
Search for: da_ and replace with: megatherium_is_awesome_
Search for: Text Domain: da and replace with: Text Domain: megatherium-is-awesome in style.css.
Search for:  da and replace with:  Megatherium_is_Awesome
Search for: da- and replace with: megatherium-is-awesome-
Then, update the stylesheet header in style.css and the links in footer.php with your own information. Next, update or delete this readme.

Now you're ready to go! The next step is easy to say, but harder to do: make an awesome WordPress theme. :)