sure, after you set up another site by the guide, you’ll access it with the GET parameter
https://eleven.openemr.io/e/openemr/interface/login/login.php?site=default
so for mynewsite instead of default
https://eleven.openemr.io/e/openemr/interface/login/login.php?site=mynewsite
then the session will remember this after login and operate out of the correct database that you created with the multisite setup