This post is part of the where I am taking a look at Matomo which bills itself as a Google Analytics alternative that protects your data and your customers' privacy.
With Matomo installed it is now available for you to log in using your super user account. Navigate to the website and enter the credentials and click Sign In:
You'll then be taken to the page showing activity on your first site:
You can click the cog button in the top right corner (or if your page is too narrow click the hamburger icon and select Administration) to access the admin functions such as adding additional sites or adding extra users.