I’m looking at the page and I’m scared to. :$
It’s really easy 🙂
Download the zip, unzip, FTP up the files. Visit your webpage. Done.
Not quite ipstenu … and very dangerous instructions there
DO NOT upload wp-config.php in the WP root directory
(uploading wp-config-sample.php is OK)
DO NOT upload the wp-content folder
BUT DO upload the twentyten theme folder inside wp-content/themes/
Actually… Theere is no wp-config.php file in the standard wordPress download. Also there should be zero harm overwriting the wp-content folder. That’s what the auto upgrade does, after all 🙂 Done it hundreds of times, never a problem.
Taking a backup first is always recommended, of course.