my_pmprorh_init.php

<?php
/*
Plugin Name: Register Helper Example
Plugin URI: http://www.paidmembershipspro.com/wp/pmpro-customizations/
Description: Register Helper Initialization Example
Version: .1
Author: Stranger Studios
Author URI: http://www.strangerstudios.com
*/
//we have to put everything in a function called on init, so we are sure Register Helper is loaded
function my_pmprorh_init()
{
    //don't break if Register Helper is not loaded
    if(!function_exists("pmprorh_add_registration_field"))
    {
        return false;
    }

    //define the fields
    $fields = array();
   
    //only require this field if the user is logged out
    if(is_user_logged_in())
        $required = false;
    else
        $required = true;
   
   $fields[] = new PMProRH_Field(
        "skill_level", // input name, will also be used as meta key
        "select", // type of field
        array(
            "required" => $required,
            "showrequired" => true,
            "options"=>array( // <option> elements for select field
                "beginner"=>"Beginner", // <option value=”beginner”>Beginner</option>
                "intermediate"=>"Intermediate", // <option value=”intermediate”>Intermediate</option>
                "athlete"=>"Athlete" // <option value=”athelte”>Athlete</option>
            )
        )
    );

    //add the fields into a new checkout_boxes are of the checkout page
    foreach($fields as $field)
        pmprorh_add_registration_field(
            "after_pricing_fields", // location on checkout page
            $field            // PMProRH_Field object
        );

    //that's it. see the PMPro Register Helper readme for more information and examples.
}
add_action("init", "my_pmprorh_init");