As a user, you would log in here on this dashboard. LOGIN HERE.
Use the login name: dannymacwhite
Below you will see a button that says offline. This is what you would place on a page on your website.
When you are online, it will show you as online. When you are offline, it will show you as offline.
Please watch this quick video to see how to log in. You can then test being both online and offline and see how it impacts the below button(you will need to refresh this page each time).