1. You have to edit the .htaccess file as below:
DirectoryIndex index.php
RewriteEngine On
Options +FollowSymLinks
Options -Indexes
RewriteCond %{SCRIPT_FILENAME} !-d RewriteCond %{SCRIPT_FILENAME} !-f
RewriteRule . index.php [L,QSA]
2. You have to edit your apache2.conf file to allow rewrite. Your apace2.conf file is located at /etc/apache2
On the file, find the location on file which says:
<Directory /var/www/> Options Indexes FollowSymLinks AllowOverride None Require all granted </Directory>
and replace that with:
<Directory /var/www/> Options Indexes FollowSymLinks AllowOverride All Require all granted </Directory>
3. You have to enable the rewrite module. In your terminal write:
sudo a2enmod rewrite
Then RESTART apache2 for the changes to commit. The site will then show the internal pages.
sudo service apache2 restart