How to authenticate users in different tables through the public auth module in Laravel5.3

Currently, only users in the users table can be authenticated. I also want to authenticate users in the administrators table, but I don’t know how to do it.
I configured a system guard in auth.php. If it is configured as the default, it can be authenticated. However, there is no way to authenticate the users table. Is there any way to access different login forms and then use the public one? Login logic to authenticate users in different tables.