You can change the Semibox layout very easily by adding the below attribute to the body tag in the Velzon/Views/Shared/_Layout.cshtml file.

data-layout="semibox"

How to add new menu items/change menu items?

To add, change or remove menu items from the left side navigation, simply edit in file Velzon/Views/Shared/sidebar.cshtml. The change would reflect in all the HTML files automatically. We are using gulp which would take care of including the Velzon/Views/Shared/sidebar.cshtml file content in all HTML pages.