if you’re a novice, i’d recommend simply installing the Exclude Pages plugin: http://wordpress.org/extend/plugins/exclude-pages/
Unzip the plugin, then upload it to /wp-content/plugins/
Activate it, then on whichever page you’re trying to exclude, go to it and below the categories section, uncheck the exclude page section. Then Update your page so the changes are updated.
Hope this helps. There’s another method which requires editing the header.php, but honestly this plugin makes it way easier.