If you install one of the plugins that allows WP to process PHP then go back to the page where you pasted that code and be sure to click on the HTML tab (far right corner of the editor box). Then paste your code in.
If you paste your code into the editor while in visual mode, those < > will be converted into their HTML code equivalents - and effective disable the script.
To learn more about customizing WordPress, go here: [codex.wordpress.org...] Yes, I know it's a LOT to absorb - but that's what you need to do if you want to learn. :)