Login into a specific realm

When I access the Keycloak login page, and click on administration console → Login into master realm

I believe this is for admin access and control into the whole Keycloak instance.

Inside I created 2 realms, c9 and shiru.

In a similar way, I want to log in as admin to c9 and shiru (so that later I can give the admin access to these realms to the respective tenants and then they can control and manage roles for their applications).

How can I achieve the same?