Just as the error message says, you have a port conflict, the port 3306 your server needs is already in use. There is nothing specific in MySQL or MariaDB in regard to port usage.
To find out how to detect occupied ports, please read your Linux documentation. There are many utilities that you can use for that.
To resolve the conflict, you need to either stop the previous application, or to start your MariaDB server with a different port.
For further troubleshooting, please read http://dev.mysql.com/doc/refman/5.5/en/starting-server.html
and the MySQL manual in general.