RC Theme comes out of the box with onepage navigation module which works from all pages of the site, but it needs to me configured in the right way in order to give the best experience for your visitors.
The main difference between regular navigation and onepage is in that regular is used to navigate between different pages of your site, onepage is used to move between different sections of one page.
So, to properly setup that type of navigation you'll need to setup sections on your page. Open the front page in visual composer and then create a new row or section(or pick from existing ones), open it's settings and scroll to the bottom:
You will need to fill highlighted fields. First one is Row ID – this is an internal name of that section. It can only contain latin letters, numbers, dashes and underline characters. Each ID should be unique for this page. It is bad to have two elements with the same ID on a page.
Second one is the Extra class name field, this field can contain several classnames at the moment splitted by the one space symbol. To add this section to onepage navigation system you need to add there "wph-scrollspy" class.
Once you'll complete these steps, save page changes and then go to Appearance > Menus dashboard page. Here you need to link each section to it's menu item. For this you'll need to use custom links:
URL should start with your page's address. For example if your page is located at http://site.com/mypage and the section ID is "test-section", menu item URL should look like: http://site.com/mypage/#test-section
This way your link will work from all pages of your site. Repeat these steps for each section.