How to upgrade to Drupal 8 from 7 with clean install?
If I'm understanding your situation correctly in that you just want a new Drupal 8 website without any of the content from your existing Drupal 7 website then you would just simply install Drupal 8 from scratch, as if you didn't even have an old site.

Once the new Drupal 8 website is installed you can then create/re-create any content that you'd like.