If you want to build a Drupal site using a Drush make file instead of composer, set drupal_build_composer_project: false, drupal_build_makefile: true and either use the example.drupal.make.yml file as a base, or use your own Drush make file: just place it or symlink it into the root of the Drupal VM folder with the filename drupal.make.yml. You can also set a separate path to the makefile using the drush_makefile_path variable.

drupal_build_composer_project: false
drupal_build_makefile: true

Have a look at the defaults in default.config.yml and tweak the settings as you'd like in your config.yml, then run vagrant up as in the Quick Start Guide. Within a few minutes, you should have your site running and available at the drupal_domain configured in config.yml, falling back to the default http://drupalvm.test set in default.config.yml.

With the default settings the Drupal site will be built on the VM inside /var/www/drupalvm/drupal/web but the web/ subdirectory is only required for composer based projects and you can simplify this directory structure by setting drupal_core_path to /var/www/drupalvm/drupal.

drupal_build_composer_project: false
drupal_build_makefile: true
drupal_core_path: "/var/www/drupalvm/drupal"