If you want to add a Piwik installation which is protected via basic access authentication (for example using a .htaccess file), you just have to add the username and password to the Piwik Server URL between the protocol and domain like this:

https://basicauth_username:basicauth_password@domain.tld/directory

Example: https://myusername:secret@demo.piwik.org

Note: we highly recommend to use https so you don’t send your password in plain text over the wire.