Changing Admin Username

I want to change the admin username. When I go to the User’s Profile in the WP Dashboard I find this text next to the Username – Usernames cannot be changed. Evidently, the change needs to be made in the wp_users table in the database. I can get to the screen to enter a new username for user_login. In the middle of the screen is a Function box with a arrow to click on to select function options. Do you know what function option to select to proceed to change the user_login?

Also, I’ve read that if you change the database user account and password then you need to also make the same change in the ‘wp-config.php’ file. Does ‘database user account’ refer to the username such as ‘admin’ or is it referring to the database ID?

Also, concerning changing my login password. I find that I can change my password by going to the User’s Profile in the WP Dashboard. Is this password the login password? I find that I can change my login password in the wp_users table in the database by finding a screen to change user_pass. In the middle of the screen is a Function box with a arrow to click to select function options. Do you know what function option to select to proceed to change the user_pass?