STEP 1: How to trigger a Popup from a Nav menu item?
You can have a mega menu navigation using the Popup Elementor feature. Please check the detailed tutorial below:
https://elementor.com/help/how-to-trigger-a-popup-from-a-nav-menu-item/
This is the CSS class added to the Company menu item:
mega-menu-company
Tip: If you don't see the CSS Classes field, ensure it's enabled in the Screen Options:
STEP 2: How to edit the Company popup mega menu?
The Company navigation item leads to the "Company Mega Menu – H. Big Manufacturing" popup. You can locate this template in Dashboard > Templates > Popups.
Click on "Edit with Elementor" to edit the menu, images, button's link, etc.
Read more about the Elementor Popups
https://elementor.com/help/how-do-i-create-my-first-popup/
Another way to quickly access the Company Mega Menu is to mouse over the "Edit with Elementor" link and click on the corresponding popup link:
The popup's "Display Conditions" setting determines where the mega menu will be displayed. Check this guide for more details: Why mega menu isn't visible on inner pages?
Please check these guides for further information:
https://elementor.com/help/elementors-theme-builder/
Follow the above steps for customizing the Solutions/Produts/R&D/Media/Careers menu as well.