public function navButtonSubmit(array &$form, FormStateInterface &$form_state) {
    $storage = $form_state->getStorage();
    // Save steps values to storage.
    if ($form_state->getValue('location')) {
      $storage['location'] = $form_state->getValue('location');
    }
    if ($form_state->getValue('type')) {
      $storage['type'] = $form_state->getValue('type');
    }
    $form_state->setStorage($storage);
    $form_state->setRebuild();
  }