You need to install PHP 7.1.3 or greater FPM version.
sudo apt install php7.2-fpm php7.2-mbstring php7.2-xmlrpc php7.2-soap php7.2-gd php7.2-xml php7.2-cli php7.2-zip
Install nginx from apt
sudo apt install nginx
Install Composer, php dependency manager.
curl -sS https://getcomposer.org/installer | sudo php -- --install-dir=/usr/local/bin --filename=composer