You have just installed MariaDB server for the first time.

You can start it via:
 systemctl start mariadb
or
 rcmysql start

During the first start, empty database will be created for you automatically.

PLEASE REMEMBER TO SET A PASSWORD FOR THE MariaDB root USER!
To do so, start the server and run the following commands:

'/usr/bin/mysqladmin' -u root password 'new-password'
'/usr/bin/mysqladmin' -u root -h <hostname> password 'new-password'

Alternatively you can run:
'/usr/bin/mysql_secure_installation'

which will also give you the option of removing the test
databases and anonymous user created by default. This is
strongly recommended for production servers.