Upload the wp-announcements folder to the plugins directory in your WordPress or WPMU installation.
Activate the plugin.
To display the marquee in your website: Call the php function wp_announce_marquee('') anywhere in your theme, use the WP-Announce-Marquee Widget or use the Shortcode [wp_announce_marquee] anywhere in your post or page content.
For posts checked off as popup announcements: The Popup will popup a new browser window by default unless you specify otherwise, some visitors may receive a popup blocker alert from their browser. Using the Shadowbox JS or ThickBox WordPress plugins are recommended, just upload and activate either plugin and save your popup type.
Check marquee or/and popup announcement on any post add/edit page on the bottom left under categories.
Manage announcements from the admin page located under "Settings>WP-Announcements".
That's it! A Marquee or Popup will be displayed promoting your announcement.