Modification of a Wordpress Menu - (Two Menu System) + Documentation

Hello, I have installed the site: [login to view URL] with wordpress and the template avada. ([login to view URL]) I d like to get the same menu structure on my page as it is on this page [login to view URL] This page is useing a "two menu system". The target should be, if you scroll down on each menu point, that also the sub-menu title is getting highlighted. Next point is, that the top menu should be in bigger letters and it should be next to the logo. (like on the aletto page) The Sub-Menu should be in smaller letter and straight under the main menu, with a little grey background. (like on the aletto page) The highlight color of the sub menu points should be red (like on the paletto page) The explanation how it works can be found here. (i guess) [login to view URL] But after i do not have the time and i am not familiar with the HTML code, i need support. At the moment the sub menu points are realised as an drop down menu. The target is to implement this three submenues to the correct menue point in the top menue. This changes should be done in the child theme. Please consider, that the menu structure should also work for mobile devices. That means, it have to be responsive ! Please also describe in text and pictures, how you implement it, so that I can do it by my other pages by my own. You will get administrator access to the backend of the wordpress page and you will get FTP access to the server. I have attached a PDF with pictures and explanation. Should be not a big deal to do it Thanks Martin