I want to record some day-specific information in a user's entry so that when I display their entry using a view, I can display this information.  My plan was:

1. Use the action from the entry being created - frm_after_create_entry
2. Call a function which changes the value of some hidden fields in the form
3. Use the normal view to display these 

I cannot find the function in the help docs to actually set a value.  I have found the ones to get a value, but I need to set it. 

This is the function ultimately being called from the user having added and entry, and it works as expected.  Just need the code to actually change a value, or understand what would be an alternative way of approaching this.

This help documentation https://formidableforms.com/knowledgebase/set-values-to-be-used-in-custom-displays-or-default-values/ doesn't show any usable PHP, only shortcodes.

function tw_add_day_data_to_entry($entry_id, $form_id ){
  $entry = FrmEntry::getOne($entry_id);
  $user_id = $entry->user_id;

  if ( ! $user_id ) {
      return; //don't continue if no user
  }
  //
  $day = tw_return_status();
  $url = tw_home_page()."/day-".$day;
  echo "Day= ".$day;
  echo "URL= ".$url; // at this point they return a value
  $dayURL =  FrmProEntriesController::get_field_value_shortcode(array('field_id' ='IDn8jec', 'entry' => $entry_id));
  echo $dayURL;
  $day =  FrmProEntriesController::get_field_value_shortcode(array('field_id' ='9q904', 'entry' => $entry_id));
  echo $day;
}