Disable the default Apache virtual host:
sudo a2dissite 000-default.conf
nano /etc/apache2/sites-available/example.com.conf
< VirtualHost *:80>
ServerAdmin webmaster@example.com
ServerName example.com
ServerAlias www.example.com
DocumentRoot /var/www/example.com/public_html/
ErrorLog /var/www/example.com/logs/error.log
CustomLog /var/www/example.com/logs/access.log combined
< VirtualHost>->