After installing and activating SEO Booster, go to the admin menu item, "SEO Booster".
First installed, the dashboard is empty, data is still being gathered from visitors.
Read more about the Dashboard page here - cleverplugins.helpscoutdocs.com/article/18-dashboard
The keywords page contains all the information about the keywords visitors use to find your website on search engines.
Check out all the features and how to use them here: Features category.