There are two ways for installing the Drupal Console. In both of them, there are two steps. These comments are for Linux or Mac machines.
a) Using composer
Run this command
$ composer global require drupal/console:@stable --prefer-dist
or this command if you want to keep the commands "drupal site:mode dev" and "drupal site:mode dev" that were removed in newer releases
$ composer global require drupal/console:0.11.3 --prefer-dist