keycloak-rest-api

To create the user using the Keycloak Rest API, one just need to request from the admin-cli client a token on behalf of the admin user by providing its name and password, for instance as follows:

IMO if one is starting to learn Keycloak one should avoid using the master Realm or change the admin_cli configuration like that without a very good reason.

From the Keycloak documentation one can read:

When you boot Keycloak for the first time Keycloak creates a pre-defined realm for you. This initial realm is the master realm. It is the highest level in the hierarchy of realms. Admin accounts in this realm have permissions to view and manage any other realm created on the server instance. When you define your initial admin account, you create an account in the master realm. Your initial login to the admin console will also be via the master realm.

We recommend that you do not use the master realm to manage the users and applications in your organization. Reserve use of the master realm for super admins to create and manage the realms in your system. Following this security model helps prevent accidental changes and follows the tradition of permitting user accounts access to only those privileges and powers necessary for the successful completion of their current task.

So typically you would create a different Realm, and create the users there. Unless, you really want to create a user on the master realm, typically admin-alike users.

That being said to create the user using the Keycloak Rest API, one just need to request from the admin-cli client a token on behalf of the admin user by providing its name and password, for instance as follows: