You want to install the four core components that compose LAPP. That is you want to install Apache, Postgres and PHP on Ubuntu Linux (which comes with Perl pre-installed). How do you do this?
1. Install Ubuntu. If you need directions, see this link.
2. Run this command:
sudo apt-get -y install php apache2-bin postgresql postgresql-contrib php-pgsql libapache2-mod-php
# Please note that the postgresql-contrib is an optional package.
3. You are done. You may also want to see these relevant postings:
How Do You Deploy LAPP with Frontend User Authentication?
How Can You Accept User Input with PHP and Use It in a SQL Command?