Login to DirectAdmin control panel from http://yourdomain:2222 or http://yourserverIP:2222. Once you logged into the DirectAdmin panel, click on MySQL Management in the Your Account section.
You will then see a list of all existing databased on your server. Above the database list, you can see Create new Database and phpMyAdmin. Click the Create new Database link.
Then type in your database name, create a new database user or choose an existing user from the drop-down list. Type in the password for the database user twice if you choose to create a new user for the new database. Finally hit the Create button the create the MySQL database in DirectAdmin control panel.