Save a lot of your time by scrolling less in WP admin! A small UX improvement will always keep Publish Button and Main Admin Menu within reach.
Upload plugin folder to the '/wp-content/plugins/' directory
Activate the plugin through the 'Plugins' menu in the WordPress admin
Change settings on Settings -> Toolbar Publish Button if you wish
Enjoy the clone of the Update / Publish button on the admin top toolbar when editing posts, pages and custom post types.