This is for the launcher. You have to download a compressed version (tar or zip) from
Next, you have to run inside of the uncompressed folder
$ composer install
$ box build
This will create the launcher drupal.phar. You can move it to /usr/bin/local to make available anywhere.
Do not forget that in addition you must add the Drupal Console each time you work over a Drupal installation
$ composer require drupal/console:~1.0 --prefer-dist --optimize-autoloader