Change the below attribute in the body tag in the Views/Shared/_Layout.cshtml file to set Hovered sidebar style.

data-sidebar-size="sm-hover"

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 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 Views/Shared/_sidebar.cshtml file content in all HTML pages.