How to create a new parent section on the Configuration page?
Here is a way to do it.
#example_codes.links.menu.yml
example_codes.base:
  title: 'Example Codes Module'
  parent: system.admin
  description: 'A Module with various Examples.'
  route_name: example_codes.base
  weight: 0

You need to define system.admin as parent.
And in your routing.yml should contain this base route.
#example_codes.routing.yml
example_codes.base:
  path: '/admin/examples-codes'
  defaults:
    _controller: '\Drupal\system\Controller\SystemController::systemAdminMenuBlockPage'
    _title: 'Example Codes Module'
  requirements:
    _permission: 'administer example codes configurations'