How does ActiveDirectoryLdapAuthenticationProvider work without explicitly specifying user credentials?

Question

Following is a typical example of what I've found on the Internet for Authenticating to Active Directory using LDAP.

package com.test;

import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.ldap.authentication.ad.ActiveDirectoryLdapAuthenticationProvider;

@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        ActiveDirectoryLdapAuthenticationProvider adProvider = new ActiveDirectoryLdapAuthenticationProvider("domain.org",
                "ldap://activedirectory-url:389");
        adProvider.setConvertSubErrorCodesToExceptions(true);
        adProvider.setUseAuthenticationRequestCredentials(true);
        auth.authenticationProvider(adProvider);
    }

}

Let's say I have a user XYZ with password 123 which I enter into the login form. How would this security configuration pickup my credentials and verify them against the Active Directory server?

Why does Active Directory not require a ManagerDn, ManagerPassword, or Username or Userpassword. I fail to understand how it would Authenticate without the aforementioned information.

Normally with ldapAuthentication I would provide such details in the ContextSource, like so:

but I can't seem to find how do this with ActiveDirectoryLdapAuthenticationProvider .

I checked the class's documentation and was unable to understand how it receives and processes the userCredentials