If you havn't already, download the latest version of starkBlog from here.
Extract the tarball to your web server.
Chmod your config.php file to be writible (aka to 777)
Point your browser to http://your-site.com/starkBlog/install.php and fill in the information required. If all goes well, it will tell you.
IMPORTANT: chmod your config.php file to 644!
To upgrade from 0.2 to 0.3, you will need to use a special update script, to be released at a later time. Check back soon for it!
To update, simply copy your blog_backend.php file to a temporary seperate directory, extract the new tarball, and copy blog_backend.php back.