Login to your MySQL root account (or any other account with admin privileges):

mysql -u root -p

Create the database you want your new user to be associated with:

CREATE DATABASE example_database;

Create the new user:

CREATE USER 'example_user'@'localhost' IDENTIFIED BY 'password';

Grant the new user access to the newly created database:

GRANT ALL ON example_database.* TO 'example_user'@'localhost';

Login to MySQL with your new user:

mysql -u example_user -p

Check the databases under the new user:

show databases;

Build something awesome!