A while back, we shared a mobile menu hack that helps you create a collapsing nested menu. We know many of you have used it, but with the new Divi Theme Builder, the approach becomes slightly different. In today’s tutorial, we’ll show you how to apply a mobile collapsing effect to the Menu Module inside the Divi Theme Builder. There are three main parts to this tutorial:

Setting up your menu and assigning the correct classes to your menu items
Building your menu using the Theme Builder and Menu Module
Adding the custom code inside the Theme Builder
You’ll be able to download the template JSON file for free as well! Let’s get to it.

Read more: https://www.elegantthemes.com/blog/divi-resources/how-to-create-a-mobile-collapsing-nested-menu-with-divis-theme-builder