Now, let's get to it.
Open a terminal window and run the following commands:
sudo apt-get install apache2 mysql-server php5 libapache2-mod-php5 php5-xsl php5-gd php-pear libapache2-mod-auth-mysql php5-mysql
sudo sed -i ‘s/; extension=mysql.so/extension=mysql\.so/g' /etc/php5/apache2/php.ini
#That's a series of 3 spaces after ‘s/;
sudo /etc/init.d/apache2 restart
Reboot and you're done!
What do those commands do? Well, the first one installs all of the packages needed. The second one uses sed to remove the semicolon (which denotes a comment) from the php config file, thus allowing php to work with mysql. The third one simply restarts apache.
In the above commands, there should only be 3 lines. Your display settings may cause the commands to span more than 3 lines. If so, just copy and paste line by line. Each command begins with sudo.