Hi Taehee,
It is your theme that dictates the width and position of your menus, so you would first need to find a theme that has a layout that replicates what you’re looking for. I don’t think TwentyTwenty would be a good starting point. GeneratePress has a full width menu by default, so that might be a better choice, but ultimately it is up to you.
Then, follow these steps to get started: https://www.megamenu.com/articles/getting-started/
There are a lot of steps to creating the demo menu, so I can’t list them all here sorry, but everything can be found in our documentation. Most of the menu could be made using the free version, but certain things, e.g. adding a logo, requires Pro. For example, the documentation for adding a logo can be found here: https://www.megamenu.com/documentation/menu-logo/ (the same can be found for the search box, badges etc).
Regards,
Tom
