You can change the Semibox layout very easily by adding the below attribute to the html tag in the src/main/resources/templates/layout.html 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 src/main/resources/templates/partials/sidebar.html. The change would reflect in all the HTML files automatically.