MariaDB and MySQL are both compatible with each other, the decision is on system administrator which one will be used.
MariaDB instalation:
apt-get install mariadb-server mariadb-client apt-get install php5-mysqlnd php5-apcu service apache2 restart
MySQL Instalation:
apt-get install mysql-server mysql-client apt-get install php5-mysql php5-apcu service apache2 restart
You can always go back and check those posts:
Linux – Apache Part 1: Instalation and configuration
Linux – Apache Part 2: Enable SSL
After now your server should be ready to use 🙂