Under Downloads, click the download link and save the plugin to your desktop.
Then go to your site, login and go to WP Admin > Plugins > Add New > Upload Plugin
Upload the plugin zip file from your desktop and activate.
Next, go to WP Admin > POS > Settings > License and enter your License Key and License Email to complete the activation.
You can download WooCommerce POS Pro on your account page
When new versions are ready they will appear in your Updates dashboard. For information on what I am currently working on, please key an eye on the Roadmap. Also keep an eye on the change log which will list the new features for each version and the documentation page will be updated with information on how to use the new features.