Your Main Navigation menu is placed on the Main Header of your website. Here you can change the names of the existing menu and submenu items, create new ones, rearrange them, link them to internal or external page etc.
Customize it the way you want in order to build your best navigation structure. In this way you will bring more intuitive user experience for your readers and higher conversion rates for you.
Add sidebar menus next to your text and create shortcuts to the similar topics. You can create different menus on different pages, but also use the same one menu on multiple pages.