apt-get update
apt-get install apache2

a2dissite 000-default
service apache2 reload

mkdir -p /var/www/example-site/

Place the actual html files etc. into the website directory.

Alternatively, populate the directory from another source, such as:

git clone https://github.com/example/example-site.git
cp -r example/* /var/www/example-site

chown -R www-data:www-data /var/www/example-site

Base the config file on the default config file.

cp /etc/apache2/sites-available/000-default.conf /etc/apache2/sites-available/example-site.conf

vi /etc/apache2/sites-available/example-site.conf

between

<VirtualHost *:80>
  ServerName example-site
  DocumentRoot /var/www/example-site
</VirtualHost>

a2ensite example-site.conf
service apache2 reload

Within a web-browser enter

http://example-site