You must have PHP 4.3 or higher installed. Should work like any other WordPress plugin. Upload the oceia-bar directory to wp-content/plugins. Turn it on under Plugins in the WordPress administration.
Just a note -- you need wp_head() in your header file and wp_footer() in your footer file for Oceia bar to work out of the box. See the FAQ for workarounds.
WordPress recommends turning off a plug-in before you upgrade it, but Oceia bar doesn't use any database connections, so you probably don't need to. Other than that, all you've got to do to upgrade is upload the updated oceia-bar directory and you're good to go.
If you're upgrading from Oceia bar 1.x, you'll want to re-do your custom CSS: the process has changed considerably.




