I have no idea how to upgrade!
I know how to install but that is about it. A sticky on it might be nice, and a link to the upgrader too.
Upgrading from which version?
Upgrading from 1.6.0 to 1.6.1
The wiki instructions should be sufficient, but in a nut shell, deactivate all plugins, close your board via the ACP, upload the changed files from the blog announcement, browse to yoursite.com/install/upgrade.php, and follow the instructions.