Please follow below steps to create a brand new mega menu from scratch. However, we recommend using existing mega menu (if it has come with your theme) and customize for ease of use.
1) First go to "Mega Menus" section from Left admin bar. Then click "Add New".
2. Add Mega Menu name. Let's say, new mega menu name is New Mega Menu.
After you save the menu, it'll appear under Mega Menu section of Appearance -> Menus as shown in screenshot.
Step3: Now edit the Mega Menu you created using Elementor
Step 4: Design your menu as you want.
Step 5: Now go to Menus
Step 6.Click on "Screen Options" and select "Mega Menus" and "CSS classes".
Step 7. Select menu from menu dropdown or create new menu
8. Now you need to add your created mega Menu in Website menus. Expand "Mega Menus" section and Select menu name which you want to add in your menu. You can add New Mega Menu (which you have just created) or select any other mega menu to be included under Website Menu as shown below.
When done, then Click "Add to Menu" and "Save Menu"
For create new menu. Please set Display location "Primary"
then "Save Menu".
You may check this video. Above process is shown in video