The AMP plugin adds support for the Accelerated Mobile Pages (AMP), which is all about providing mobile optimized content that can load instantly everywhere.
The plugin is available for free in wordpress.org repository. You can download it or install directly from the WP admin panel › Plugins › Add new panel.
As any other plugin from wordpress.org site, when new version of the plugin is available, you will be notified about it directly in your Dashboard.
All you need to do to enable AMP support on your site is to activate the plugin. The theme will do the rest.
Check the AMP version of a post
To check how Google will deliver your post content on mobile devices, please add the /amp/ part to the end of its url, like this:
Post url: http://yourdomain.com/some-post/
AMP version: http://yourdomain.com/some-post/amp/
If you want to learn more about Google's AMP project, please read the What Is Google AMP And How Will It Affect Your SEO? article.