The plugin is very easy to use. Simply install and activate it then visit your admin area dashboard Settings -> Sticky Popup screen and add the content you like showing in the popup box.
You can put HTML code, add images, use shortcodes etc inside your popup content. The plugin allows you to use a custom popup header color, icon and title.
You can set popup position to right, left, right bottom or left bottom. When you are done with options, save the changes, visit the frontend of your website to see how it looks like.