Add Nested  List into $form I have something like this. How can I make $upload_items be a nested &lt;ul&gt; list under Upload examples 

Something like 

&lt;ul&gt;
  &lt;li&gt; Upload Ex &lt;/li&gt;
    &lt;ul&gt;
      &lt;li&gt; YAY &lt;/li&gt;
    &lt;/ul&gt;
&lt;/ul&gt;


What I have now

$upload_items = array(
  'PDF',
  'Video',
  'PNG, GIF, JPG, JPEG',
);
 $step_items = array(
    'Upload Examples',
    implode('&lt;/li&gt;&lt;li&gt;',$upload_items),
    'Describe The Project',
    'Assign Tags',
    'School/Company',
  );
 $form['step_list'] = array(
    '#prefix' =&gt; '&lt;ul class="step_list"&gt;&lt;li&gt;',
    '#markup' =&gt; implode('&lt;/li&gt;&lt;li&gt;', $step_items),
    '#suffix' =&gt; '&lt;/li&gt;&lt;/ul&gt;',
   );


Also, what is an easy way to add ids to these &lt;li&gt;
Using #markup is ok, you want to use theme_item_list to easily build your list and add html attributes to it:
https://api.drupal.org/api/drupal/includes%21theme.inc/function/theme_item_list/7