Using Composer to create a Drupal site

You can download Drupal using Composer, the de facto PHP package manager. The preferred method is to use the Drupal Composer project template provided by the community.

To build your Drupal 8 site, run the following commands:

$ cd /path/to/document/root
$ composer create-project drupal-composer/drupal-project drupal8 --stability dev

Wait for the commands to finish--it may take some time, as it downloads all the required dependencies. You can feel free to grab a coffee (the first time takes a while; it primes caches. Have faith, it will be much faster the next time.)

When finished, you will find a different directory structure inside your drupal8 directory. The vendor directory contains all third-party PHP libraries, and the web directory contains your Drupal 8 site. You will need to modify your web server to use the web directory as the new docroot within your drupal8 directory.

The project and its details can be found at https://github.com/drupal-composer/drupal-project, along with its full documentation.