designtopack/public/site/models/project.php

<?php

class ProjectPage extends Page {
  public function getSteps() {    

    $steps = array_map(function($child) {
      return [
        'text' => $child['content']['title'],
        'value' => $child['content']['stepname']
      ];
    }, $this->children()->toArray());

    return $steps;
  }
}