I followed these steps, taken from James Tansley, on this post https://www.digitalocean.com/community/articles/how-to-install-wordpress-on-ubuntu-12-04
1. Go to /etc/apache2/mods-enabled/ directory. To do this, type "cd /etc/apache2/mods-enabled/" without the quotes.
2. Open the dir.conf file so you can edit it. To do this, type "sudo nano dir.conf" without the quotes.
3. You will see a line of index files (index.html, index.php, index.cgi, etc) under the DirectoryIndex setting. Add index.php as the first item in the list. Doing so will tell Apache to first look for and load an index.php file before looking for the other index file extensions.
4. Press Ctrl+X to save your changes and then press Enter to exit the editor.
5. Restart Apache by typing "sudo /etc/init.d/apache2 restart" without the quotes.
WordPress is a free and open source website and blogging tool that uses php and MySQL. It was created in 2003 and has since then expanded to manage 22% of all the new websites created and has over 20,000 plugins to customize its functionality. This tutorial shows how to install WordPress on a server with LAMP. It is written for Ubuntu 12.04.