Show Bitrix subsections?

Question

1C-Bitrix

There is a template for catalog.section.list

<? if (!defined("B_PROLOG_INCLUDED") || B_PROLOG_INCLUDED !== true) die();
$this->setFrameMode(true);
?>

<div class="menu">
  <div class="menu__list">
  <?foreach ($arResult["SECTIONS"] as $arSection):?>
      <div class="menu__item"><a class="menu__link" href="<?= $arSection["SECTION_PAGE_URL"] ?>">
        <div class="menu__img">
          <img class="menu__pic" src="<?=$arSection["PICTURE"]["SRC"]?>" title="<?=$arSection["NAME"]?>" border="0"/>
        </div>
        <div class="menu__title"><?= $arSection["NAME"] ?></div>
          <svg class="menu__svg">
            <use xlink:href="<?=SITE_TEMPLATE_PATH?>/images/icons/sprite.svg#angle-r"></use>
          </svg></a>
        </div>
        <?endforeach;?>
      </div>
     <div class="submenu">
          <a class="submenu__item" href="">Подраздел</a>
      </div>
</div>

How to display submenu in div submenu?