How to set Main Menu in Header.
Go to Online Store -> Customize -> Theme Settings -> Header & Megamenu Option
Remember, Any changes in Theme settings will effect on entire store.
* Select the cart method, there are two options
1. Ajax Cart:- When you do "Add To Cart", one sidebar will appear at right side of you screen displaying cart products.
2. Redirect to cart page:- When you click on "Add To Cart" button, user will directly redirected to the cart page.
* Header Menu
Select the main menu for header. Your Main Header Menu will display like below image.
* Set Megamenu width.
* Megamenu background color.
* Megamenu top-bottom padding.
* Megamenu left-right padding.
See the below attach image to have an idea about How your complete Menu will Look?